Control method and control device

Abstract

Provided is a control method which is performed by a control device. This control method includes a step in which, while an electric vehicle is being charged using a charger at a facility comprising a power storage device, and a natural-energy power generation device, and the charger for charging an electric vehicle, reverse power flow from the facility to a power grid is reduced by controlling charging power or discharging power of the power storage device when the reverse power flow becomes larger than an upper limit value.

Description

Control Method and Control Device

[0001] The present disclosure relates to a control method and the like performed by a control device.

[0002] There is known a system including a charger for charging an electric vehicle and a solar power generation facility as an example of a natural energy power generator. For example, Patent Document 1 discloses a system including a charger and a solar power generation facility, in which surplus power generated by the solar power generation facility is supplied to the charger. This system is used in sites such as charging stations, for example.

[0003] Japanese Unexamined Patent Application Publication No. 2021-177674

[0004] By the way, when a condition is satisfied such that reverse power flow from a site where a charger for an electric vehicle and a natural energy power generator are installed to a power grid exceeds an upper limit, problems caused by reverse power flow occur, such as equipment failure or power outage.

[0005] Therefore, the present disclosure provides a control method and the like that suppress the occurrence of problems caused by reverse power flow.

[0006] A control method according to an aspect of the present disclosure is a control method performed by a control device, comprising the step of: in a facility including a charger for charging an electric vehicle, a power storage device, and a natural energy power generator, when reverse power flow from the facility to a power grid becomes larger than an upper limit while the electric vehicle is being charged by the charger, controlling charging power or discharging power of the power storage device to reduce the reverse power flow.

[0007] Further, a control device according to an aspect of the present disclosure includes: a storage that stores an upper limit of reverse power flow to a power grid from a facility including a charger for charging an electric vehicle, a power storage device, and a natural energy power generator; and a controller that, when reverse power flow from the facility to the power grid becomes larger than the upper limit while the electric vehicle is being charged by the charger in the facility, controls charging power or discharging power of the power storage device to reduce the reverse power flow.

[0008] These comprehensive or specific embodiments may be implemented as systems, devices, methods, integrated circuits, computer programs, or non-temporary recording media such as computer-readable CD-ROMs, or as any combination of systems, devices, methods, integrated circuits, computer programs, and recording media.

[0009] The control method described in one aspect of this disclosure can suppress the occurrence of problems caused by reverse power flow.

[0010] Figure 1 is a block diagram showing an example of the configuration of a control system according to the embodiment. Figure 2 is a diagram showing a specific example of equipment provided at a site according to the embodiment. Figure 3 is a flowchart of operation example 1 performed by the control device according to the embodiment. Figure 4 is a flowchart of operation example 2 performed by the control device according to the embodiment. Figure 5 is a flowchart of operation example 3 performed by the control device according to the embodiment. Figure 6 is a flowchart of operation example 4 performed by the control device according to the embodiment. Figure 7A is a flowchart of operation example 5 performed by the control device according to the embodiment. Figure 7B is a flowchart of another first example of operation example 5 performed by the control device according to the embodiment. Figure 7C is a flowchart of another second example of operation example 5 performed by the control device according to the embodiment. Figure 8 is a diagram showing the predicted power value detected by the power meter according to the embodiment. Figure 9 is a flowchart of operation example 6 performed by a modified control device. Figure 10 is a flowchart of operation example 7 performed by a modified control device.

[0011] In the future, electric vehicles (EVs) are expected to become widespread. Sites equipped with chargers for these electric vehicles may also be equipped with energy storage devices or renewable energy power generation devices. If the discharge power from the energy storage device or the power generated by the renewable energy power generation device becomes excessively large, reverse power flow may occur from this facility (hereinafter sometimes referred to as "site") to the power grid, and this reverse power flow may exceed the upper limit.

[0012] When conditions are met such as the reverse power flow exceeding the upper limit, problems caused by the reverse power flow occur. Examples of these problems include equipment failure or power outages, the inability of renewable energy power generation equipment to generate electricity, or the disruption of a stable power supply from the power grid. A more specific example of this problem is as follows: The equipment mentioned above includes grid equipment such as substations, and transformers installed at the boundary between the power grid and the electrical wiring within facilities equipped with renewable energy power generation equipment. Furthermore, when the reverse power flow exceeds the capacity of the grid equipment, the power outage occurs due to power interruption caused by the failure of the grid equipment. When such a power outage occurs, the renewable energy power generation equipment detects this outage and stops generating electricity. In addition, this power outage disrupts the stable power supply from the power grid.

[0013] Furthermore, while Patent Document 1 discloses that surplus power generated by a renewable energy power generation device is supplied to a charger to suppress reverse power flow, it does not disclose a control method for controlling the energy storage device. Therefore, if a charging station or similar site disclosed in Patent Document 1 is equipped with an energy storage device, the above-mentioned problem may occur if the energy storage device is not properly controlled.

[0014] Therefore, the control method according to Example 1 is a control method performed by a control device, and in a facility equipped with a charger for charging electric vehicles, an energy storage device and a natural energy power generation device, when the electric vehicle is being charged by the charger, if the reverse power flow from the facility to the power grid exceeds an upper limit, the control method includes the step of controlling the charging power or discharging power of the energy storage device to reduce the reverse power flow.

[0015] This controls the charging or discharging power of the energy storage device, reducing the reverse power flow. As a result, the reverse power flow is less likely to exceed the upper limit, suppressing problems caused by reverse power flow. In other words, a control method is realized that suppresses problems caused by reverse power flow.

[0016] Furthermore, the control method according to Example 2 may be the control method according to Example 1, wherein when the reverse power flow exceeds the upper limit, the discharge power of the energy storage device is reduced to reduce the reverse power flow.

[0017] This reduces the discharge power flowing back from the energy storage device into the power grid, thus lowering the reverse power flow. As a result, the reverse power flow becomes less likely to exceed the upper limit. In other words, a control method is realized that suppresses the occurrence of problems caused by reverse power flow. Furthermore, by reducing the discharge power of the energy storage device, the amount of charge required for subsequent energy storage devices is reduced, thus lowering charging costs.

[0018] Furthermore, the control method according to Example 3 may be the control method according to Example 2, wherein if the reverse power flow during the planned discharge period of the energy storage device exceeds the upper limit, the discharge power of the energy storage device is reduced to reduce the reverse power flow.

[0019] As a result, if the reverse power flow from the energy storage device exceeds the upper limit during the planned discharge period, the discharge power flowing back into the power grid from the energy storage device decreases, thus reducing the reverse power flow. Consequently, the reverse power flow becomes less likely to exceed the upper limit. In other words, a control method is realized that suppresses the occurrence of problems caused by reverse power flow.

[0020] Furthermore, the control method according to Example 4 may be the control method according to Example 3, in which, even when a suppression mode is not set to reduce the reverse power flow to below the upper limit using the energy storage device, if the reverse power flow becomes greater than the upper limit during the planned discharge period of the energy storage device, the discharge power of the energy storage device is reduced to reduce the reverse power flow.

[0021] As a result, even when suppression mode is not set, if the reverse power flow from the energy storage device to the power grid is greater than the upper limit during the planned discharge period of the energy storage device, the discharge power flowing back from the energy storage device to the power grid will decrease, thus reducing the reverse power flow. Consequently, even when suppression mode is not set, the reverse power flow becomes less likely to exceed the upper limit. In other words, a control method is realized that suppresses the occurrence of problems caused by reverse power flow.

[0022] Furthermore, the control method according to Example 5 may be a control method according to any of Examples 2 to 4, which includes the step of reducing the power generation of the natural energy power generation device and reducing the reverse power flow if the reverse power flow is greater than the upper limit even after reducing the discharge power of the energy storage device.

[0023] As a result, if the reverse power flow exceeds the upper limit even after reducing the discharge power of the energy storage device, the power generated by the renewable energy generator and the power grid will decrease, thus reducing the reverse power flow. Consequently, the reverse power flow becomes less likely to exceed the upper limit. In other words, a control method is realized that suppresses the occurrence of problems caused by reverse power flow. Furthermore, as a control to reduce reverse power flow, reducing the discharge power of the energy storage device takes priority over reducing the power generated by the renewable energy generator, making it possible to mitigate the decrease in revenue associated with a decrease in the amount of electricity sold to the power grid by the renewable energy generator.

[0024] Furthermore, the control method according to Example 6 may be a control method according to any of Examples 2 to 4, which includes the step of increasing the charging power of the charger and reducing the reverse power if the reverse power flow is greater than the upper limit even when the discharge power of the energy storage device is reduced.

[0025] As a result, if the reverse power flow exceeds the upper limit even after reducing the discharge power of the energy storage device, the power consumed by the charger will increase, thus reducing the reverse power flow from the facility to the power grid. Consequently, the reverse power flow becomes less likely to exceed the upper limit. In other words, a control method is realized that suppresses the occurrence of problems caused by reverse power flow. Furthermore, as a control to reduce reverse power flow, reducing the discharge power of the energy storage device takes priority over increasing the charging power of the charger, making it possible to suppress the degradation of the battery in the electric vehicle that occurs due to an increase in the charging power of the charger.

[0026] Furthermore, the control method according to Example 7 may be the control method according to Example 2, wherein, with a suppression mode set to keep the reverse power flow below the upper limit using the energy storage device, if the reverse power flow exceeds the upper limit during the planned discharge period of the energy storage device, the discharge power of the energy storage device is reduced to reduce the reverse power flow; and, with the suppression mode not set, if the reverse power flow exceeds the upper limit during the planned discharge period of the energy storage device, the discharge power of the energy storage device is not reduced, but the power generation power of the natural energy power generation device is reduced to reduce the reverse power flow.

[0027] Thus, when the suppression mode is set, if the reverse power flow exceeds the upper limit during the planned discharge period of the energy storage device, the energy storage device reduces its discharge power. This reduces the discharge power flowing back from the energy storage device to the power grid, thus reducing the reverse power flow. As a result, the reverse power flow becomes less likely to exceed the upper limit. Also, when the suppression mode is not set, if the reverse power flow exceeds the upper limit during the planned discharge period of the energy storage device, the power generated by the renewable energy power generator is reduced. This reduces the power generated back from the renewable energy power generator to the power grid, thus reducing the reverse power flow. As a result, the reverse power flow becomes less likely to exceed the upper limit. In other words, a control method is realized that suppresses the occurrence of problems caused by reverse power flow.

[0028] Furthermore, the control method according to Example 8 is a control method according to Example 2, which includes a step of reducing the discharge power of the energy storage device to reduce the reverse power flow power when, in a state in which a suppression mode is set to keep the reverse power flow power below the upper limit value using the energy storage device, the reverse power flow power exceeds the upper limit value during the planned discharge period of the energy storage device, and when, in a state in which the suppression mode is not set, the reverse power flow power exceeds the upper limit value during the planned discharge period of the energy storage device, the charger's charging power is increased without reducing the discharge power of the energy storage device to reduce the reverse power flow power.

[0029] Thus, when the suppression mode is set, if the reverse power flow exceeds the upper limit during the planned discharge period of the energy storage device, the energy storage device reduces its discharge power. This reduces the discharge power flowing back from the energy storage device to the power grid, thus reducing the reverse power flow. As a result, the reverse power flow becomes less likely to exceed the upper limit. Also, when the suppression mode is not set, if the reverse power flow exceeds the upper limit during the planned discharge period of the energy storage device, the charger's charging power is increased. This increases the power consumed by the charger, thus reducing the reverse power flow from the facility to the power grid. As a result, the reverse power flow becomes less likely to exceed the upper limit. In other words, a control method is realized that suppresses the occurrence of problems caused by reverse power flow.

[0030] Furthermore, the control method according to Example 9 may also be a control method according to Example 2, Example 3, Example 7, or Example 8, which includes a step of charging the energy storage device to reduce the reverse power flow if, while a suppression mode is set to reduce the reverse power flow to below the upper limit using the energy storage device, the discharge power of the energy storage device is reduced, and the reverse power flow is still greater than the upper limit.

[0031] Thus, when the suppression mode is set and the discharge power of the energy storage device is reduced, if the reverse power flow still exceeds the upper limit, the energy storage device is charged. This generates charging power, which is the power consumed by the energy storage device, and the reverse power flow decreases by the amount of this charging power consumed by the energy storage device. As a result, the reverse power flow becomes less likely to exceed the upper limit. In other words, a control method is realized that suppresses the occurrence of problems caused by reverse power flow.

[0032] Furthermore, the control method according to Example 10 may be the control method according to Example 9, further comprising the step of reducing the power output of the natural energy power generation device to reduce the reverse power output if the reverse power output is greater than the upper limit even after charging the energy storage device.

[0033] As a result, if the reverse power flow exceeds the upper limit even after charging the energy storage device, the amount of power generated from the renewable energy power generation device that flows back into the power grid will decrease, thus reducing the reverse power flow. Consequently, the reverse power flow becomes less likely to exceed the upper limit. In other words, a control method is realized that suppresses the occurrence of problems caused by reverse power flow. Furthermore, as a control to reduce reverse power flow, charging the energy storage device with power generated by the renewable energy power generation device takes priority over reducing the power generated by the renewable energy power generation device, making it possible to reduce the charging cost of the energy storage device.

[0034] Furthermore, the control method according to Example 11 may be the control method according to Example 9, further comprising the step of increasing the charging power of the charger to reduce the reverse power flow if the reverse power flow is greater than the upper limit value even when the energy storage device is charged.

[0035] As a result, if the reverse power flow exceeds the upper limit even after charging the energy storage device, the power consumed by the charger increases, thus reducing the reverse power flow from the facility to the power grid. Consequently, the reverse power flow becomes less likely to exceed the upper limit. In other words, a control method is realized that suppresses the occurrence of problems caused by reverse power flow. Furthermore, as a control to reduce reverse power flow, charging the energy storage device takes priority over increasing the charging power of the charger, making it possible to suppress the degradation of the battery in the electric vehicle that occurs due to the increase in the charging power of the charger.

[0036] Furthermore, the control method according to Example 12 may be the control method according to Example 1, wherein when the reverse power flow exceeds the upper limit, the charging power of the energy storage device is increased to reduce the reverse power flow.

[0037] As a result, the charging power consumed by the energy storage device increases, and the reverse power flow decreases by the amount of this charging power consumed by the energy storage device. Consequently, the reverse power flow becomes less likely to exceed the upper limit. In other words, a control method is realized that suppresses the occurrence of problems caused by reverse power flow.

[0038] Furthermore, the control method according to Example 13 may be the control method according to Example 12, wherein if the reverse power flow during the period of the planned charging of the energy storage device exceeds the upper limit, the charging power of the energy storage device is increased to reduce the reverse power flow.

[0039] As a result, if the reverse power flow exceeds the upper limit during the planned charging period of the energy storage device, the charging power consumed by the energy storage device increases, and the reverse power flow decreases by the amount of this consumed charging power. Consequently, the reverse power flow becomes less likely to exceed the upper limit. In other words, a control method is realized that suppresses the occurrence of problems caused by reverse power flow.

[0040] Furthermore, the control method according to Example 14 may be the control method according to Example 13, in which, even when a suppression mode is not set to reduce the reverse power flow to below the upper limit using the energy storage device, if the reverse power flow becomes greater than the upper limit during the planned charging period of the energy storage device, the charging power of the energy storage device is increased to reduce the reverse power flow.

[0041] As a result, even when suppression mode is not set, if the reverse power flow exceeds the upper limit during the planned charging period of the energy storage device, the charging power consumed by the energy storage device increases, and the reverse power flow decreases by the amount of this consumed charging power. Consequently, even when suppression mode is not set, the reverse power flow becomes less likely to exceed the upper limit. In other words, a control method is realized that suppresses the occurrence of problems caused by reverse power flow.

[0042] Furthermore, the control method according to Example 15 may be the control method according to Example 13, wherein, during the period in which the charging of the energy storage device is planned, a suppression mode is set to use the energy storage device to keep the reverse power flow below the upper limit, and if the reverse power flow exceeds the upper limit, the charging power of the energy storage device is increased to reduce the reverse power flow; and during the period in which the charging of the energy storage device is planned, the suppression mode is not set, and if the reverse power flow exceeds the upper limit, the charging power of the energy storage device is not reduced, but the power generated by the natural energy power generation device is reduced to reduce the reverse power flow.

[0043] Accordingly, in a case where reverse power flow is greater than the upper limit value while the suppression mode is set during the scheduled charging period of the power storage device, charging power, which is the power consumed by the power storage device, increases, so the reverse power flow decreases by an amount corresponding to the charging power consumed by the power storage device. As a result, reverse power flow is less likely to exceed the upper limit value. Further, in a case where reverse power flow is greater than the upper limit value while the suppression mode is not set during the scheduled charging period of the power storage device, the generated power that flows backward from the natural energy power generation device to the power system decreases, so the reverse power flow decreases. As a result, reverse power flow is less likely to exceed the upper limit value. That is, a control method that suppresses the occurrence of problems caused by reverse power flow is achieved.

[0044] Further, the control method according to Example 16 is the control method according to Example 13, wherein during the scheduled charging period of the power storage device, when the reverse power flow becomes greater than the upper limit value in a state where the suppression mode for reducing the reverse power flow to the upper limit value or less is set using the power storage device, the charging power of the power storage device is increased to reduce the reverse power flow; and during the scheduled charging period of the power storage device, when the reverse power flow becomes greater than the upper limit value in a state where the suppression mode is not set, the control method may be configured such that the charging power of the power storage device is not reduced, and the charging power of the charger is increased to reduce the reverse power flow.

[0045] Accordingly, in a case where reverse power flow is greater than the upper limit value while the suppression mode is not set during the scheduled charging period of the power storage device, charging power, which is the power consumed by the power storage device, increases, so the reverse power flow decreases by an amount corresponding to the charging power consumed by the power storage device. As a result, reverse power flow is less likely to exceed the upper limit value. Further, in a case where reverse power flow is greater than the upper limit value while the suppression mode is not set during the scheduled charging period of the power storage device, the power consumed by the charger increases, so reverse power flow from the facility to the power system decreases. As a result, reverse power flow is less likely to exceed the upper limit value. That is, a control method that suppresses the occurrence of problems caused by reverse power flow is achieved.

[0046] Further, the control method according to Example 17 is a control method according to any one of Examples 12 to 16, and may be a control method comprising the step of: when the reverse power flow power is larger than the upper limit value even if the charging power of the power storage device is increased, reducing the generated power of the natural energy power generation device to reduce the reverse power flow power.

[0047] Accordingly, when the reverse power flow power is still larger than the upper limit value even after increasing the charging power of the power storage device, the generated power that flows backward from the natural energy power generation device to the power grid decreases, so the reverse power flow power decreases. As a result, the reverse power flow power is less likely to exceed the upper limit value. That is, a control method that suppresses the occurrence of problems caused by reverse power flow power is realized. Furthermore, as control for reducing the reverse power flow power, increasing the charging power of the power storage device using the generated power of the natural energy power generation device is performed with priority over reducing the generated power of the natural energy power generation device, thereby making it possible to reduce the charging cost of the power storage device.

[0048] Further, the control method according to Example 18 is a control method according to any one of Examples 12 to 16, and may be a control method comprising the step of: when the reverse power flow power is larger than the upper limit value even if the charging power of the power storage device is increased, increasing the charging power of the charger to reduce the reverse power flow power.

[0049] Accordingly, when the reverse power flow power is still larger than the upper limit value even after increasing the charging power of the power storage device, the power consumed by the charger increases, so the reverse power flow power from the facility to the power grid decreases. As a result, the reverse power flow power is less likely to exceed the upper limit value. That is, a control method that suppresses the occurrence of problems caused by reverse power flow power is realized. Furthermore, as control for reducing the reverse power flow power, increasing the charging power of the power storage device is performed with priority over increasing the charging power of the charger, thereby making it possible to suppress degradation of the storage battery in the electric vehicle accompanying an increase in the charging power of the charger.

[0050] Further, the control method according to Example 19 is a control method according to Example 1, and may be a control method in which, when the reverse power flow power becomes larger than the upper limit value, the power storage device is charged to reduce the reverse power flow power.

[0051] This generates charging power, which is the power consumed by the energy storage device, and consequently, the reverse power flow decreases by the amount of this charging power consumed by the energy storage device. As a result, the reverse power flow is less likely to exceed the upper limit. In other words, a control method is realized that suppresses the occurrence of problems caused by reverse power flow.

[0052] Furthermore, the control method according to Example 20 may also be a control method according to any of Examples 13, 14, and 19, wherein, during a period when the energy storage device is not scheduled for charging, a suppression mode is set to use the energy storage device to keep the reverse power flow below the upper limit, and when the reverse power flow exceeds the upper limit, the energy storage device is charged to reduce the reverse power flow.

[0053] As a result, when the reverse power flow exceeds the upper limit while the suppression mode is set during periods when the energy storage device is not scheduled for charging, charging power, which is power consumed by the energy storage device, is generated. This reduces the reverse power flow by the amount of charging power consumed by the energy storage device. Consequently, the reverse power flow becomes less likely to exceed the upper limit. In other words, a control method is realized that suppresses the occurrence of problems caused by reverse power flow.

[0054] Furthermore, the control method according to Example 21 may be the control method according to Example 20, which includes the step of reducing the power output of the natural energy power generation device without charging the energy storage device if the reverse power flow becomes greater than the upper limit value during a period when the energy storage device is not scheduled to be charged and the suppression mode is not set.

[0055] As a result, when the reverse power flow exceeds the upper limit during periods when the energy storage device is not scheduled for charging and the suppression mode is not set, the amount of power generated from the renewable energy generator flowing back into the power grid decreases, thus reducing the reverse power flow. Consequently, the reverse power flow becomes less likely to exceed the upper limit. In other words, a control method is realized that suppresses the occurrence of problems caused by reverse power flow.

[0056] Furthermore, the control method according to Example 22 may be the control method according to Example 20, which includes the step of reducing the reverse power flow by increasing the charging power of the charger without charging the energy storage device if the reverse power flow becomes greater than the upper limit value during a period when the energy storage device is not scheduled for charging and the suppression mode is not set.

[0057] As a result, when the reverse power flow exceeds the upper limit during periods when the energy storage device is not scheduled for charging and the suppression mode is not set, the power consumed by the charger increases, thus reducing the reverse power flow from the facility to the power grid. Consequently, the reverse power flow becomes less likely to exceed the upper limit. In other words, a control method is realized that suppresses the occurrence of problems caused by reverse power flow.

[0058] Furthermore, the control method according to Example 23 may be a control method according to Example 19 or Example 20, which includes a step of reducing the power output of the natural energy power generation device and reducing the reverse power output if the reverse power flow is greater than the upper limit even after charging the energy storage device.

[0059] As a result, if the reverse power flow exceeds the upper limit even after charging the energy storage device, the amount of power generated from the renewable energy generator flowing back into the power grid will decrease, thus reducing the reverse power flow. Consequently, the reverse power flow is less likely to exceed the upper limit. In other words, a control method is realized that suppresses the occurrence of problems caused by reverse power flow.

[0060] Furthermore, the control method according to Example 24 may also be a control method according to Example 19 or Example 20, which includes a step of increasing the charging power of the charger and decreasing the reverse power flow if the reverse power flow is greater than the upper limit value even when the energy storage device is charged.

[0061] As a result, if the reverse power flow exceeds the upper limit even after charging the energy storage device, the power consumed by the charger increases, thus reducing the reverse power flow from the facility to the power grid. Consequently, the reverse power flow becomes less likely to exceed the upper limit. In other words, a control method is realized that suppresses the occurrence of problems caused by reverse power flow.

[0062] Furthermore, the control method according to Example 25 may also be a control method according to any of Examples 6, 8, 11, 16, 18, 22, and 24, which includes a step of reducing the power output of the natural energy power generation device and reducing the reverse power output if the reverse power output is greater than the upper limit even when the charging power of the charger is increased.

[0063] As a result, if the reverse power flow exceeds the upper limit even after increasing the charging power of the charger, the power generated by the renewable energy generator and the power grid will decrease, thus reducing the reverse power flow. Consequently, the reverse power flow will be less likely to exceed the upper limit. In other words, a control method that suppresses the occurrence of problems caused by reverse power flow is realized. Furthermore, as a control to reduce reverse power flow, the increase in the charging power of the charger using the power generated by the renewable energy generator takes priority over the decrease in the power generated by the renewable energy generator, making it possible to reduce the facility's electricity costs.

[0064] Furthermore, the control device according to Example 26 is a control device comprising: a memory for storing the reverse power flow from a facility equipped with a charger for charging electric vehicles, an energy storage device, and a natural energy power generation device to the power grid; and a controller that, when the electric vehicle is being charged by the charger at the facility, controls the charging power or discharging power of the energy storage device to reduce the reverse power flow when the reverse power flow from the facility to the power grid exceeds an upper limit.

[0065] This controls the charging or discharging power of the energy storage device, reducing the reverse power flow. As a result, the reverse power flow is less likely to exceed the upper limit, suppressing problems caused by reverse power flow. In other words, a control device is realized that suppresses problems caused by reverse power flow.

[0066] Furthermore, these comprehensive or specific embodiments may be implemented as systems, devices, methods, integrated circuits, computer programs, or non-temporary recording media such as computer-readable CD-ROMs, or as any combination of systems, devices, methods, integrated circuits, computer programs, and recording media.

[0067] The embodiments will be described below with reference to the drawings. Note that the embodiments described below are either comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement and connection configurations of components, steps, and the order of steps shown in the following embodiments are examples only and are not intended to limit the scope of the claims.

[0068] (Embodiment) [Configuration] Figure 1 is a block diagram showing an example of the configuration of the control system 100 according to this embodiment. Figure 2 is a diagram showing a specific example of the equipment provided by site 120 according to this embodiment.

[0069] The control system 100 shown in Figure 1 comprises a control device 110 and a site 120. Site 120 is an example of a facility equipped with a charger 121 for charging electric vehicles V, a power storage device 122, and a renewable energy power generation device 124, and is a so-called charging site. In the control system 100, the control device 110 controls the power storage device 122, which is an example of the equipment provided at site 120.

[0070] Although only one charger 121 is shown in Figure 1, site 120 may have multiple chargers 121. In other words, a charging site has at least one charger 121. A charging site may also be referred to as a charging station.

[0071] Furthermore, although only one energy storage device 122 is shown in Figure 1, site 120 may have multiple energy storage devices 122. In other words, site 120 has at least one energy storage device 122.

[0072] Site 120 may also include a power meter 200 and buildings 123 such as commercial facilities, factory facilities, government offices, research facilities, and rest facilities. Buildings 123 are equipped with loads that consume electricity.

[0073] In such a site 120, the discharged power, which is the power discharged by the energy storage device 122, may be consumed as charging power for the charger 121 to charge the electric vehicle V, may be consumed by the load of the building 123, or may be used for selling electricity. In addition, the generated power produced by the natural energy power generation device 124 may be consumed as charging power for the charger 121 to charge the electric vehicle V, may be consumed by the load of the building 123, or may be used for selling electricity.

[0074] Site 120 may also be equipped with a power meter 200. The power meter 200 may detect the power passing through it, and more specifically, it may detect the reverse power flow from Site 120 to the power system 300. The power passing through the power meter 200 may correspond to the connection point power. Reverse power flow refers to the reverse flow of the discharge power of the energy storage device 122 or the generated power of the renewable energy power generation device 124 into the power system 300. For example, if the sum of the discharge power of the energy storage device 122 and the generated power of the renewable energy power generation device 124 is greater than the total power consumed within Site 120, the surplus power will flow back into the power system 300. The total power consumed within Site 120 is the sum of the charging power of the charger 121, the power consumed by the load of the building 123, and the charging power charged by the energy storage device 122. The reverse power flow travels from site 120 through power meter 200 to power grid 300.

[0075] The control device 110 may be, for example, a computer, which controls the energy storage device 122 as described above. Alternatively, the control device 110 may control the natural energy power generation device 124 or the charger 121.

[0076] The control device 110 controls the charging power or discharging power of the energy storage device 122. The control device 110 may decrease or increase the charging power of the energy storage device 122, or decrease or increase the discharging power of the energy storage device 122. Alternatively, for example, the control device 110 may control the power generated by the renewable energy power generation device 124. The control device 110 may decrease or increase the power generated by the renewable energy power generation device 124. Alternatively, for example, the control device 110 may control the charging power of the charger 121. The control device 110 may decrease or increase the charging power of the charger 121.

[0077] As shown in Figure 1, the control device 110 includes a controller 111 and a memory unit 112.

[0078] The controller 111 is, for example, a circuit that performs information processing such as information input processing, output processing, and arithmetic processing. The controller 111 may be a processor such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit), or it may be composed of multiple circuit elements. The operation of the control device 110 is basically performed by the controller 111. For example, the controller 111 may control the charger 121, the energy storage device 122, and the natural energy power generation device 124.

[0079] The controller 111 may acquire information for controlling the charger 121, the energy storage device 122, and the renewable energy power generation device 124. The controller 111 may accept information input via an input interface or receive information via a communication interface. For example, the controller 111 may acquire information indicating the reverse power flow detected by the power meter 200.

[0080] Furthermore, the controller 111 may output information for controlling the charger 121, the energy storage device 122, and the renewable energy power generation device 124. The controller 111 may output information via an output interface or transmit information via a communication interface.

[0081] The memory 112 is, for example, a memory device that stores information. The memory 112 may also be a circuit. Furthermore, the memory 112 may be a volatile memory or a non-volatile memory. Also, the memory 112 may be composed of multiple memory elements.

[0082] The memory unit 112 stores the reverse power flow from site 120 to power system 300.

[0083] For example, the controller 111 acquires information indicating reverse power flow from the communication interface of the power meter 200, and the reverse power flow indicated by the acquired information is stored in the memory 112. The controller 111 acquires information indicating reverse power flow at regular intervals, such as between a few seconds and a few minutes, and each time such information is acquired, the reverse power flow stored in the memory 112 is updated. If no reverse power flow is generated, the information indicating reverse power flow should indicate that no reverse power flow is generated.

[0084] When the electric vehicle V is being charged by the charger 121, if the reverse power flow exceeds the upper limit, the controller 111 controls the charging or discharging power of the energy storage device 122 to reduce the reverse power flow. Here, an example in which the reverse power flow stored and updated in the memory 112 exceeds the upper limit will be explained using the first and second examples of the upper limit.

[0085] The upper limit in the first example may be a predetermined value determined by the contract between the administrator of the control system 100 and the power company, which is the administrator of the power grid 300. If the time during which the reverse power flow exceeds the upper limit in the first example exceeds a predetermined time, a problem caused by the reverse power flow occurs. When the controller 111 detects that the reverse power flow exceeds the upper limit in the first example, that is, when it detects that the reverse power flow exceeds the upper limit in the first example, it performs the following processing. At this time, the controller 111 controls the charging power or discharging power of the energy storage device 122 to reduce the reverse power flow so that the time during which the reverse power flow exceeds the upper limit in the first example is within a predetermined period.

[0086] The upper limit for the second example may be a predetermined value determined by the contract between the administrator of the control system 100 and the power company, which is the administrator of the power grid 300, i.e., a value less than the upper limit for the first example. The upper limit for the second example is, for example, a value between 90% and 99% of the upper limit for the first example. The upper limit for the second example is a value that ensures a margin, or safety margin, relative to the upper limit for the first example. When the controller 111 detects that the reverse power flow is greater than the upper limit for the second example, that is, when it detects that the reverse power flow is greater than the upper limit for the second example, it performs the following processing. At this time, the controller 111 controls the charging power or discharging power of the energy storage device 122 to reduce the reverse power flow. In this embodiment, the upper limit for the second example is used as the upper limit.

[0087] Furthermore, the upper limit for the first example and the upper limit for the second example may be stored in the memory device 112.

[0088] Next, I will explain the facilities that Site 120 is equipped with.

[0089] The charger 121 is a charging facility for charging an electric vehicle V. The electric vehicle V is, for example, a plug-in hybrid vehicle (PHV) or a battery electric vehicle (BEV), but is not limited to these.

[0090] In an example where the charger 121 is controlled by the controller 111, if the reverse power flow is greater than the upper limit, the controller 111 may increase the charging power of the charger 121, that is, the power that the charger 121 uses to charge the electric vehicle V. As a result, the power consumed by the charger 121 increases, that is, the power consumed within site 120 increases, and the reverse power flow from site 120 to the power system 300 decreases. Consequently, the reverse power flow becomes less likely to exceed the upper limit.

[0091] The charger 121 may acquire information for controlling the charger 121 output from the control device 110 and be controlled according to the acquired information. The charger 121 may acquire such information, for example, through a communication interface provided in the charger 121. If the information instructs the charger 121 to reduce its charging power, the charger 121 reduces its charging power. If the information instructs the charger 121 to increase its charging power, the charger 121 increases its charging power.

[0092] The energy storage device 122 is a device that stores electricity supplied from the power grid 300 or discharges the stored electricity, and is composed of, for example, a lithium-ion battery or a nickel-metal hydride battery, but is not limited to these. In this embodiment, the energy storage device 122 is a stationary device installed at the site 120, unlike batteries mounted on electric vehicles V, etc.

[0093] In an example where the energy storage device 122 is controlled by the controller 111, the controller 111 may reduce the discharge power of the energy storage device 122 if the reverse power flow is greater than the upper limit. As a result, the discharge power flowing back from the energy storage device 122 to the power system 300 decreases, thus reducing the reverse power flow. Consequently, the reverse power flow becomes less likely to exceed the upper limit.

[0094] Another example of the energy storage device 122 being controlled by the controller 111 is when the reverse power flow is greater than the upper limit and the controller 111 charges the energy storage device 122. This generates charging power, which is the power consumed by the energy storage device 122, and thus increases the total power consumed within the site 120. As a result, the reverse power flow decreases by the amount of charging power consumed by the energy storage device 122. Consequently, the reverse power flow becomes less likely to exceed the upper limit.

[0095] Thus, when the electric vehicle V is being charged by the charger 121, if the reverse power flow from the power system 300 at site 120 exceeds the upper limit, the controller 111 controls the charging or discharging power of the energy storage device 122 to reduce the reverse power flow. This makes it less likely for the reverse power flow to exceed the upper limit. In other words, a control device 110 and control method are realized that suppress the occurrence of problems caused by reverse power flow.

[0096] The energy storage device 122 may acquire information for controlling the energy storage device 122 output from the control device 110 and be controlled according to the acquired information. The energy storage device 122 may acquire such information, for example, through a communication interface provided in the energy storage device 122. If the information instructs the energy storage device 122 to start charging, the energy storage device 122 starts charging. If the information instructs the energy storage device 122 to decrease its charging power, the energy storage device 122 decreases its charging power. If the information instructs the energy storage device 122 to increase its charging power, the energy storage device 122 increases its charging power. If the information instructs the energy storage device 122 to start discharging, the energy storage device 122 starts discharging. If the information instructs the energy storage device 122 to decrease its discharge power, the energy storage device 122 decreases its discharge power. If the information instructs the energy storage device 122 to increase its discharge power, the energy storage device 122 will increase its discharge power.

[0097] The renewable energy power generation device 124 is an energy conversion device that converts natural energy into generated electricity. The renewable energy power generation device 124 is composed of, for example, a solar power generation system, a wind power generation system, or a geothermal power generation system, but is not limited to these.

[0098] As described above, the electricity generated by the natural energy power generation device 124 may be supplied to the charger 121 or the load of the building 123, or it may be used for selling electricity.

[0099] In an example where the renewable energy power generation device 124 is controlled by the controller 111, the controller 111 may reduce the power generated by the renewable energy power generation device 124 if the reverse power flow is greater than the upper limit. As a result, the power generated that flows back from the renewable energy power generation device 124 to the power grid 300 decreases, thus reducing the reverse power flow. Consequently, the reverse power flow becomes less likely to exceed the upper limit.

[0100] The renewable energy power generation device 124 may acquire information for controlling the renewable energy power generation device 124 output from the control device 110 and be controlled according to the acquired information. The renewable energy power generation device 124 may acquire such information, for example, through a communication interface provided by the renewable energy power generation device 124. If the information instructs the renewable energy power generation device 124 to reduce its power generation, the renewable energy power generation device 124 will reduce its power generation. If the information instructs the renewable energy power generation device 124 to increase its power generation, the renewable energy power generation device 124 will increase its power generation.

[0101] By the way, in this embodiment, the three operating modes of the energy storage device 122 may be used.

[0102] The first operating mode is a mode in which the energy storage device 122 is charged, or it may be a charging mode. In the charging mode, the energy storage device 122 is charged by power supplied, for example, from the power grid 300. The period during which the charging mode is performed is planned before the charging mode is performed, and the control device 110 creates a schedule indicating that period. The control device 110 then executes a charging mode in which the energy storage device 122 is charged during that period, according to the created schedule. This period is referred to as the planned charging period for the energy storage device 122.

[0103] The second operating mode is a mode in which the energy storage device 122 discharges, and may also be a discharge mode. The period during which the discharge mode is performed is planned in advance, similar to the period during which the charging mode is performed, and the control device 110 creates a schedule indicating this period. The control device 110 then executes the discharge mode in which the energy storage device 122 discharges during the period according to the created schedule. This period is referred to as the planned discharge period of the energy storage device 122.

[0104] The third operating mode may be a suppression mode that uses the energy storage device 122 to reduce the reverse power flow to below an upper limit. When the suppression mode is set, the control device 110 controls the charging or discharging power of the energy storage device 122 to reduce the reverse power flow. The period during which the suppression mode is performed is planned in advance, similar to the period during which the charging mode is performed, and the control device 110 creates a schedule indicating that period. The control device 110 then executes the suppression mode during that period according to the created schedule.

[0105] Each of the three operating modes is a mode set for the entire control system 100. The control system 100 may also have other modes set in addition to the three operating modes described above. Furthermore, the control system 100 may have both a suppression mode and a charging mode set, or both a suppression mode and a discharge mode set.

[0106] The controller 111 may acquire information indicating the operating mode of the energy storage device 122. For example, the administrator of the control system 100 may input this information via an input interface, and the controller 111 may acquire the input information and create the above schedule based on the acquired information. In other words, the administrator of the control system 100 can determine the operating mode to be set for the control system 100. In addition, information indicating the operating mode set for the control system 100, that is, information indicating the operating mode that the control system 100 is currently executing, may be stored in the memory 112.

[0107] The power system 300 is, for example, a commercial power source and performs functions such as power generation, transformation, transmission, and distribution.

[0108] Next, we will explain operation examples 1 to 5 related to the control method performed by the control device 110.

[0109] [Operation Example 1] Figure 3 is a flowchart of Operation Example 1 performed by the control device 110 according to this embodiment.

[0110] Operation Example 1 is an operation performed when the electric vehicle V is being charged by the charger 121. The controller 111 may also acquire information from the communication interface of the charger 121 indicating that the charger 121 is charging the electric vehicle V. This allows the controller 111 to detect that the electric vehicle V is being charged.

[0111] In Operation Example 1, examples are shown in which the control system 100 is set to suppression mode and in which it is not set. In addition, in Figure 3, an example is shown in which the control system 100 is not set to charge mode or discharge mode.

[0112] First, the controller 111 determines whether or not a suppression mode is set for the control system 100 (S22). As described above, information indicating the operating mode set for the control system 100 is often stored in the memory 112, and the controller 111 performs the process in step S22 based on this information stored in the memory 112.

[0113] Next, if the suppression mode is set (Yes in S22), the controller 111 determines whether the reverse power flow from site 120 to power system 300 is greater than the upper limit (S10). For example, the controller 111 compares the reverse power flow stored in memory 112 with the upper limit and performs the process in step S10.

[0114] The operation terminates if the reverse power flow does not exceed the upper limit (No in S10).

[0115] If the reverse power flow exceeds the upper limit (Yes in S10), the controller 111 determines whether the reverse power flow will exceed the upper limit even if the energy storage device 122 is charged at the maximum charging power (S12). The maximum charging power of the energy storage device 122 means the maximum power that the energy storage device 122 can charge.

[0116] Information indicating the maximum charging power of the energy storage device 122 may be stored in the memory 112 beforehand. For example, the controller 111 performs the process in step S12 based on the reverse power flow power, maximum discharge power, and upper limit value stored in the memory 112. If the answer in step S10 is Yes, the controller 111 may calculate the excess amount, which is the difference between the reverse power flow power and the upper limit value.

[0117] If the reverse power flow exceeds the upper limit even when the energy storage device 122 is charging at maximum charging power (Yes in S12), the controller 111 controls the energy storage device 122 to charge at maximum charging power (S14). More specifically, the controller 111 outputs information via the communication interface instructing the energy storage device 122 to charge at maximum charging power, the energy storage device 122 acquires the outputted information, and charges at maximum charging power according to the acquired information.

[0118] Furthermore, if the reverse power flow does not exceed the upper limit when the energy storage device 122 is charged at maximum charging power (No in S12), the controller 111 controls the energy storage device 122 to charge the excess amount (S16). In other words, the controller 111 controls the energy storage device 122 to charge the power corresponding to the excess amount. More specifically, the controller 111 outputs information via the communication interface instructing the energy storage device 122 to charge the power corresponding to the excess amount, and the energy storage device 122 acquires the outputted information and charges the power corresponding to the excess amount calculated as described above according to the acquired information.

[0119] Furthermore, if the suppression mode is not set in the control system 100 (No in S22), the operation ends. In this way, if the suppression mode is not set, even if the reverse power flow exceeds the upper limit, the energy storage device 122 will not be charged as shown in steps S14 and S16.

[0120] Thus, the control method according to this example of operation may, when the reverse power flow exceeds the upper limit, charge the energy storage device 122 to reduce the reverse power flow. More specifically, the control method according to this example of operation may, when the suppression mode is set and the reverse power flow exceeds the upper limit during a period when there is no charging plan for the energy storage device 122, charge the energy storage device 122 to reduce the reverse power flow.

[0121] In this example, when the reverse power flow exceeds the upper limit, the energy storage device 122 charges power equivalent to the maximum charging power or the excess, as shown in steps S14 and S16. This process is performed even when the energy storage device 122 is not scheduled to charge and the suppression mode is set.

[0122] As a result, charging power, which is the power consumed by the energy storage device 122, is generated, that is, the total power consumed within the site 120 increases, and the reverse power flow decreases by the amount of charging power consumed by the energy storage device 122. As a result, the reverse power flow becomes less likely to exceed the upper limit, and the occurrence of problems caused by reverse power flow is suppressed. In other words, a control method and control device 110 that suppress the occurrence of problems caused by reverse power flow is realized.

[0123] As mentioned above, site 120 may be equipped with multiple energy storage devices 122. In this case, for example, in step S12, the controller 111 may determine whether the reverse power flow exceeds the upper limit even if each of the multiple energy storage devices 122 is charged at its maximum charging power. In step S14, the controller 111 may control each of the multiple energy storage devices 122 to charge at its maximum charging power. In step S16, the controller 111 may also control the multiple energy storage devices 122 as a whole to discharge the excess. In this case, the sum of the charging powers charged by each of the multiple energy storage devices 122 should correspond to the excess.

[0124] [Operation Example 2] Figure 4 is a flowchart of Operation Example 2 performed by the control device 110 according to this embodiment.

[0125] Operation Example 2 is an operation performed when the electric vehicle V is being charged by the charger 121. In Operation Example 2, the control system 100 is set to charging mode, and therefore Figure 4 is a flowchart showing the charging mode in operation. The control system 100 may or may not be set to suppression mode.

[0126] First, the energy storage device 122 is charged with the planned charging power (S20). For example, the controller 111 outputs information indicating the planned charging power via the communication interface, the energy storage device 122 acquires the outputted information, and is charged with the charging power indicated by the acquired information.

[0127] Furthermore, the controller 111 determines whether or not a suppression mode is set for the control system 100 (S22). As described above, information indicating the operating mode set for the control system 100 is often stored in the memory 112, and the controller 111 performs the process in step S22 based on the information stored in the memory 112.

[0128] If the suppression mode is set (Yes in S22), the controller 111 executes the suppression mode (S24). That is, the controller 111 performs the processing from step S10 onwards in the operation example 1 shown in Figure 3. Thus, in step S22, the processing of step S22 in Figure 3 is not performed.

[0129] Furthermore, if the suppression mode is not set (No in S22), the operation ends.

[0130] Thus, in the control method relating to this example of operation, during the period in which the charge of the energy storage device 122 is planned, if a suppression mode is set to keep the reverse power flow below an upper limit using the energy storage device 122, and the reverse power flow exceeds the upper limit, the charging power of the energy storage device 122 may be increased to reduce the reverse power flow.

[0131] In this operational example, when the suppression mode is set during the planned charging period of the energy storage device 122, if the reverse power flow exceeds the upper limit, the charging power of the energy storage device 122 is increased. An example of increasing the charging power of the energy storage device 122 is when, in the process of step S24, the energy storage device 122 increases its charging power to the maximum charging power as shown in step S14 of Figure 3. Another example of increasing the charging power of the energy storage device 122 is when, in the process of step S24, the energy storage device 122 charges the excess amount as shown in step S16 of Figure 3.

[0132] As a result, the charging power, which is the power consumed by the energy storage device 122, increases, that is, the total power consumed within the site 120 increases, and the reverse power flow decreases by the amount of the charging power consumed by the energy storage device 122. As a result, the reverse power flow becomes less likely to exceed the upper limit. In other words, a control method and control device 110 that suppress the occurrence of problems caused by reverse power flow is realized.

[0133] As mentioned above, site 120 may be equipped with multiple energy storage devices 122. In this case, for example, in step S20, each of the multiple energy storage devices 122 may be charged with the planned charging power.

[0134] [Operation Example 3] Figure 5 is a flowchart of Operation Example 3 performed by the control device 110 according to this embodiment.

[0135] Operation Example 3 is an operation performed when the electric vehicle V is being charged by the charger 121. In Operation Example 3, the charging mode is set in the control system 100, and therefore Figure 5 is a flowchart showing the execution of the charging mode. Note that the charging mode shown in Operation Example 3 is an example of another form of the charging mode shown in Operation Example 2. In addition, the control system 100 may or may not have a suppression mode set.

[0136] First, the energy storage device 122 is charged with the planned charging power (S20). In this example, the planned charging power may be less than the maximum charging power of the energy storage device 122. Information indicating the planned charging power may be stored in the memory 112.

[0137] Furthermore, the controller 111 determines whether the reverse power flow from site 120 to power system 300 is greater than the upper limit (S10).

[0138] If the reverse power flow exceeds the upper limit (Yes in S10), the controller 111 determines whether the difference between the maximum charging power of the energy storage device 122 and the planned charging power is less than the excess amount, which is the amount by which the reverse power flow exceeds the upper limit (S26). As described above, the information indicating the maximum charging power of the energy storage device 122 is stored in the memory 112. The planned charging power is the charging power planned in step S20, and the information indicating the planned charging power is also stored in the memory 112.

[0139] Based on the information indicating the maximum charging power of the energy storage device 122 and the information indicating the planned charging power stored in the memory 112, the controller 111 calculates the difference by subtracting the planned charging power in step S20 from the maximum charging power of the energy storage device 122. Based on this difference and the excess amount which is the difference between the reverse power flow power and the upper limit, the controller 111 performs the processing in step S26.

[0140] If the difference is smaller than the excess amount (Yes in S26), the controller 111 controls the energy storage device 122 to charge to the maximum charging power (S14).

[0141] If the difference is greater than or equal to the excess amount (No in S26), the controller 111 controls the charging power of the energy storage device 122 to increase by the excess amount (S28). That is, the controller 111 controls the charging power of the energy storage device 122 to increase by the amount of power corresponding to the excess amount. More specifically, the controller 111 outputs information via the communication interface instructing the energy storage device 122 to increase its charging power by the amount of power corresponding to the excess amount, and the energy storage device 122 acquires the outputted information and increases its charging power by the amount of power corresponding to the excess amount according to the acquired information. In this case, the charging power of the energy storage device 122 is the sum of the charging power being charged in step S20 and the power corresponding to the excess amount.

[0142] Furthermore, if the reverse power flow does not exceed the upper limit (No in S10), the operation terminates.

[0143] Thus, in this example of operation, the control method may increase the charging power of the energy storage device 122 to reduce the reverse power flow when the reverse power flow exceeds the upper limit. Specifically, in this example of operation, if the reverse power flow exceeds the upper limit during the period in which the energy storage device 122 is scheduled to be charged, the control method may increase the charging power of the energy storage device 122 to reduce the reverse power flow.

[0144] This control method increases the charging power of the energy storage device 122 when the reverse power flow exceeds the upper limit. Examples of increasing the charging power of the energy storage device 122 include charging the energy storage device 122 to its maximum charging power, as shown in step S14, or increasing the charging power of the energy storage device 122 by the amount of power equivalent to the excess, as shown in step S28. This process is performed during the period of the energy storage device 122's planned charging.

[0145] As a result, the charging power, which is the power consumed by the energy storage device 122, increases, that is, the total power consumed within the site 120 increases, and the reverse power flow decreases by the amount of the charging power consumed by the energy storage device 122. As a result, the reverse power flow becomes less likely to exceed the upper limit. In other words, a control method and control device 110 that suppress the occurrence of problems caused by reverse power flow is realized.

[0146] Furthermore, even when a suppression mode is not set to keep the reverse power flow below the upper limit using the energy storage device 122, the control method according to this example of operation may increase the charging power of the energy storage device 122 to reduce the reverse power flow if the reverse power flow exceeds the upper limit during the period in which the energy storage device 122 is scheduled to charge.

[0147] This control method increases the charging power of the energy storage device 122 when the reverse power flow exceeds the upper limit. The above example is an example of increasing the charging power of the energy storage device 122.

[0148] As a result, even when the suppression mode is not set, if the reverse power flow is greater than the upper limit during the planned charging period of the energy storage device 122, the charging power, which is the power consumed by the energy storage device 122, increases. In other words, the total power consumed within the site 120 increases, and the reverse power flow decreases by the amount of the charging power consumed by the energy storage device 122. As a result, even when the suppression mode is not set, the reverse power flow is less likely to exceed the upper limit. In other words, a control method and control device 110 that suppresses the occurrence of problems caused by reverse power flow are realized.

[0149] As described above, site 120 may be equipped with multiple energy storage devices 122. In this case, for example, in step S20, each of the multiple energy storage devices 122 may be charged with the planned charging power. In step S26, the controller 111 may calculate the difference between the maximum charging power and the planned charging power for each of the multiple energy storage devices 122, and determine whether the sum of the calculated differences is less than the excess amount, which is the amount by which the reverse power flow exceeds the upper limit. In step S14, the controller 111 may control each of the multiple energy storage devices 122 to charge with the maximum charging power. In step S28, the controller 111 may control each of the multiple energy storage devices 122 to increase its charging power by a predetermined amount. The sum of the predetermined amounts corresponding to each of the multiple energy storage devices 122 may correspond to the excess amount.

[0150] [Operation Example 4] Figure 6 is a flowchart of Operation Example 4 performed by the control device 110 according to this embodiment.

[0151] Operation Example 4 is an operation performed when the electric vehicle V is being charged by the charger 121. In Operation Example 4, the control system 100 is set to discharge mode, and therefore Figure 6 is a flowchart showing the execution of the discharge mode. The control system 100 may or may not be set to suppression mode.

[0152] First, the controller 111 calculates the reverse power flow power assuming that the energy storage device 122 is discharging at the planned discharge power (S30). Specifically, the reverse power flow power calculated by the controller 111 is the reverse power flow power minus the current discharge power of the energy storage device 122, plus the planned discharge power.

[0153] For example, the controller 111 acquires information indicating the planned discharge power, information indicating the current discharge power of the energy storage device 122, and information indicating the reverse power flow detected by the power meter 200 via a communication interface. Based on this acquired information, the controller 111 calculates the reverse power flow assuming that the energy storage device 122 is discharging at the planned discharge power.

[0154] The controller 111 may perform the processing in step S30 when it acquires any one of these pieces of information.

[0155] Furthermore, the reverse power flow may be calculated using not only the actual reverse power flow, i.e., the reverse power flow detected by the power meter 200, but also the assumed reverse power flow, i.e., the calculated reverse power flow.

[0156] Furthermore, the controller 111 determines whether the calculated reverse power flow is greater than the upper limit (S31). For example, the controller 111 compares the calculated reverse power flow with the upper limit stored in the memory 112 and performs the process in step S31.

[0157] If the calculated reverse power flow exceeds the upper limit (Yes in S31), the controller 111 determines whether the discharge power of the energy storage device 122 is less than the excess amount by which the calculated reverse power flow exceeds the upper limit (S32). The discharge power of the energy storage device 122 corresponds to the planned discharge power shown in step S30.

[0158] The controller 111 performs the process in step S32 based on the information indicating the planned discharge power stored in the memory 112, and the excess amount which is the difference between the reverse power flow power and the upper limit.

[0159] If the discharge power of the energy storage device 122 is less than the excess amount (Yes in S32), the controller 111 controls the energy storage device 122 to stop discharging (S34). More specifically, the controller 111 outputs information via the communication interface instructing the energy storage device 122 to stop discharging, the energy storage device 122 receives the outputted information, and stops discharging according to the received information. In this case, the discharge power of the energy storage device 122 becomes 0.

[0160] Furthermore, the controller 111 determines whether or not the control system 100 is set to suppression mode (S22).

[0161] If the suppression mode is set (Yes in S22), the controller 111 executes the suppression mode (S24). That is, the controller 111 performs the processing from step S10 onwards in the operation example 1 shown in Figure 3. For example, in step S24, the suppression mode is executed as shown in Figure 3, and processing such as charging the energy storage device 122 shown in steps S14 and S16 is performed.

[0162] Furthermore, if the discharge power of the energy storage device 122 is greater than or equal to the excess amount (No in S32), the controller 111 controls the energy storage device 122 to discharge with power reduced by the excess amount from the planned discharge power (S36). In other words, the controller 111 controls the discharge power of the energy storage device 122, i.e., the planned discharge power, to be reduced by the amount of power equivalent to the excess. More specifically, the controller 111 outputs information via the communication interface instructing the energy storage device 122 to reduce its discharge power by the amount of power equivalent to the excess, and the energy storage device 122 acquires the outputted information and reduces the planned discharge power by the amount of power equivalent to the excess according to the acquired information. In this case, the discharge power of the energy storage device 122 will be the value obtained by subtracting the power equivalent to the excess amount from the planned discharge power shown in step S30.

[0163] Furthermore, if the calculated reverse power flow does not exceed the upper limit (No in S31), the controller 111 controls the energy storage device 122 to discharge at the planned discharge power (S300). More specifically, the controller 111 outputs information via the communication interface instructing the energy storage device 122 to discharge at the planned discharge power, and the energy storage device 122 acquires the outputted information and discharges at the planned discharge power according to the acquired information.

[0164] Furthermore, if the suppression mode is not set (No in S22), the operation ends.

[0165] Thus, in the control method relating to this example of operation, if the reverse power flow exceeds the upper limit, the discharge power of the energy storage device 122 may be reduced to reduce the reverse power flow.

[0166] In this example, when the reverse power flow exceeds the upper limit, the controller 111 reduces the discharge power of the energy storage device 122. Examples of reducing the discharge power of the energy storage device 122 include setting the discharge power of the energy storage device 122 to 0, as shown in step S34, or reducing the discharge power of the energy storage device 122 by the amount of power equivalent to the excess, as shown in step S36.

[0167] This reduces the discharge power flowing back from the energy storage device 122 to the power grid 300, thus reducing the reverse power flow. As a result, the reverse power flow is less likely to exceed the upper limit. Furthermore, by reducing the discharge power of the energy storage device 122, the amount of charge added to the energy storage device 122 is reduced, thus lowering charging costs.

[0168] Furthermore, in the control method relating to this example of operation, if the reverse power flow exceeds the upper limit during the planned discharge period of the energy storage device 122, the discharge power of the energy storage device 122 may be reduced to reduce the reverse power flow.

[0169] In this operational example, during the planned discharge period of the energy storage device 122, if the reverse power flow exceeds the upper limit, the controller 111 reduces the discharge power of the energy storage device 122. An example of reducing the discharge power of the energy storage device 122 is as described above.

[0170] As a result, the discharge power flowing back from the energy storage device 122 to the power grid 300 decreases, thus reducing the reverse power flow. Consequently, the reverse power flow is less likely to exceed the upper limit.

[0171] Furthermore, in the control method relating to this example of operation, even if a suppression mode that uses the energy storage device 122 to keep the reverse power flow below the upper limit is not set, if the reverse power flow exceeds the upper limit during the planned discharge period of the energy storage device 122, the discharge power of the energy storage device 122 may be reduced to reduce the reverse power flow.

[0172] As a result, even when the suppression mode is not set, if the reverse power flow from the energy storage device 122 to the power system 300 is greater than the upper limit during the planned discharge period of the energy storage device 122, the discharge power flowing back from the energy storage device 122 will decrease, thus reducing the reverse power flow. The above is an example of how the discharge power of the energy storage device 122 is reduced. As a result, even when the suppression mode is not set, the reverse power flow will be less likely to exceed the upper limit.

[0173] In this way, a control method and control device 110 that suppress the occurrence of problems caused by reverse power flow are realized.

[0174] As described above, site 120 may be equipped with multiple energy storage devices 122. In this case, for example, in step S30, the controller 111 may calculate the reverse power flow assuming that each of the multiple energy storage devices 122 is discharging at the planned discharge power. In step S32, the controller 111 may determine whether the sum of the discharge powers of each of the multiple energy storage devices 122 is less than the excess amount, which is the amount by which the calculated reverse power flow exceeds the upper limit. In step S34, the controller 111 may control the multiple energy storage devices 122 to stop discharging. In step S36, the controller 111 may control each of the multiple energy storage devices 122 to discharge at a power reduced by a predetermined amount from the planned discharge power. The sum of the predetermined amounts corresponding to each of the multiple energy storage devices 122 may correspond to the excess amount. In step S300, the controller 111 may cause each of the multiple energy storage devices 122 to discharge at the planned discharge power.

[0175] [Operation Example 5] Figure 7A is a flowchart of Operation Example 5 performed by the control device 110 according to this embodiment.

[0176] Operation example 5 is an operation performed when the electric vehicle V is being charged by the charger 121.

[0177] First, the controller 111 executes the operation mode of the energy storage device 122 (S40). That is, in step S40, any of the operations from operation examples 1 to 4 may be performed.

[0178] The controller 111 then determines whether the reverse power flow from site 120 to power system 300 is greater than the upper limit (S10). Note that if the processing of another step S10 has been performed in the preceding step S40, the processing of step S10 does not need to be performed.

[0179] If the reverse power flow exceeds the upper limit (Yes in S10), the controller 111 controls the charger 121 to increase its charging power (S42). More specifically, the controller 111 outputs information via the communication interface instructing the charger 121 to increase its charging power, and the charger 121 acquires the outputted information and increases its charging power according to the acquired information.

[0180] Furthermore, the process of step S10 in the second step of operation example 5 is performed.

[0181] If the reverse power flow exceeds the upper limit in the second step S10 (Yes in the second S10), the controller 111 controls the renewable energy power generation device 124 to reduce its power output (S44). More specifically, the controller 111 outputs information via the communication interface instructing the renewable energy power generation device 124 to reduce the power it is generating, and the renewable energy power generation device 124 acquires the outputted information and reduces its power output according to the acquired information.

[0182] Furthermore, if the result of the first step S10 is No, the operation terminates, and if the result of the second step S10 is No, the operation terminates.

[0183] The control method in this example of operation may include a step of reducing the power output of the natural energy power generation device 124 to reduce the reverse power output if the reverse power output is greater than the upper limit even when the charging power of the charger 121 is increased.

[0184] In this control method, if the reverse power flow is greater than the upper limit even when the charging power of the charger 121 is increased as shown in step S42, the power generated by the natural energy power generation device 124 is reduced as shown in step S44.

[0185] As a result, the power consumed by the charger 121 increases, that is, the power consumed within site 120 increases, and the reverse power flow from site 120 to the power grid 300 decreases. Furthermore, the power generated from the renewable energy power generator 124 that flows back into the power grid 300 decreases, further reducing the reverse power flow. As a result, the reverse power flow becomes less likely to exceed the upper limit.

[0186] In this way, a control method and control device 110 that suppress the occurrence of problems caused by reverse power flow are realized. Furthermore, as a control to reduce reverse power flow, an increase in the charging power of the charger 121 using the power generated by the renewable energy power generation device 124 is prioritized over a decrease in the power generated by the renewable energy power generation device 124, making it possible to reduce the power costs of the facility.

[0187] As mentioned above, site 120 may be equipped with multiple energy storage devices 122. In this case, for example, in step S40, the controller 111 may execute an operating mode for each of the multiple energy storage devices 122.

[0188] [Another First Example of Operation Example 5] Figure 7B is a flowchart of another first example of operation example 5 performed by the control device 110 according to this embodiment.

[0189] Another first example of operation example 5 is an operation performed when the electric vehicle V is being charged by the charger 121.

[0190] First, the controller 111 executes the operating mode of the energy storage device 122 (S40).

[0191] The controller 111 then determines whether the reverse power flow from site 120 to power system 300 is greater than the upper limit (S10).

[0192] If the reverse power flow exceeds the upper limit (Yes in S10), the controller 111 controls the renewable energy power generation device 124 to reduce its power output (S44).

[0193] Furthermore, if the reverse power flow does not exceed the upper limit (No in S10), the operation will terminate.

[0194] The control method in this example of operation may include a step of reducing the power output of the natural energy power generation device 124 to reduce the reverse power output if the reverse power output is greater than the upper limit even after reducing the discharge power of the energy storage device 122.

[0195] In this control method, for example, if the process of operation example 4 is performed in step S40, and the discharge power of the energy storage device 122 is reduced as shown in step S34 of operation example 4, but the reverse power flow is greater than the upper limit, the power generated by the natural energy power generation device 124 is reduced as shown in step S44.

[0196] As a result, the amount of power generated that flows back from the renewable energy power generation device 124 to the power grid 300 decreases, thus reducing the reverse power flow. Consequently, the reverse power flow becomes less likely to exceed the upper limit. Furthermore, as a control measure to reduce the reverse power flow, the reduction in the discharge power of the energy storage device 122 takes precedence over the reduction in the power generated by the renewable energy power generation device 124. This makes it possible to mitigate the decrease in revenue associated with the decrease in the amount of electricity sold to the power grid 300 by the renewable energy power generation device 124.

[0197] In this example of operation, when the suppression mode is not set, if the reverse power flow exceeds the upper limit during the planned discharge period of the energy storage device 122, the power generation of the natural energy power generation device 124 is reduced without reducing the discharge power of the energy storage device 122, thereby reducing the reverse power flow.

[0198] This control method, for example, performs the processing shown in operation example 4 in step S40. Then, when the suppression mode is not set, if the reverse power flow is greater than the upper limit during the planned discharge period of the energy storage device 122, this control method reduces the power generated by the natural energy power generation device 124, as shown in step S44 of Figure 7B.

[0199] As a result, the amount of power generated and flowing back from the renewable energy power generation device 124 to the power grid 300 decreases, thus reducing the reverse power flow. Consequently, the reverse power flow becomes less likely to exceed the upper limit.

[0200] The control method in this example of operation may include a step of reducing the power output of the renewable energy power generation device 124 to reduce the reverse power output if the reverse power flow is greater than the upper limit even after charging the energy storage device 122.

[0201] This control method, for example, executes the suppression mode of step S24 of operation example 4 in step S40. In this suppression mode, if the reverse power flow is greater than the upper limit even when the energy storage device 122 is charged, this control method reduces the power generated by the natural energy power generation device 124, as shown in step S44.

[0202] As a result, the amount of power generated that flows back from the renewable energy power generator 124 to the power grid 300 decreases, thus reducing the reverse power flow. Consequently, the reverse power flow becomes less likely to exceed the upper limit. Furthermore, as a control measure to reduce the reverse power flow, charging the energy storage device 122 with the power generated by the renewable energy power generator 124 takes priority over reducing the amount of power generated by the renewable energy power generator 124, making it possible to reduce the charging cost of the energy storage device 122.

[0203] In the control method described in this example, if the reverse power flow exceeds the upper limit during the planned charging period of the energy storage device 122 while the suppression mode is not set, the power generated by the natural energy power generation device 124 may be reduced to reduce the reverse power flow without reducing the charging power of the energy storage device 122.

[0204] This control method performs the process shown in example 2 in step S40. Then, if the reverse power flow is greater than the upper limit during the planned charging period of the energy storage device 122 when the suppression mode is not set, this control method reduces the power generated by the natural energy power generation device 124, as shown in step S44.

[0205] As a result, the amount of power generated and flowing back from the renewable energy power generation device 124 to the power grid 300 decreases, thus reducing the reverse power flow. Consequently, the reverse power flow becomes less likely to exceed the upper limit.

[0206] The control method in this example of operation may include a step of reducing the power generated by the renewable energy power generator 124 to reduce the reverse power if the reverse power flow is greater than the upper limit even when the charging power of the energy storage device 122 is increased.

[0207] In this control method, for example, if the process of operation example 3 is performed in step S40, and the charging power of the energy storage device 122 is increased as shown in step S14 of operation example 3, but the reverse power flow is greater than the upper limit, the power generated by the natural energy power generation device 124 is reduced as shown in step S44.

[0208] As a result, the amount of power generated that flows back from the renewable energy power generator 124 to the power grid 300 decreases, thus reducing the reverse power flow. Consequently, the reverse power flow becomes less likely to exceed the upper limit. Furthermore, as a control measure to reduce the reverse power flow, the increase in the charging power of the energy storage device 122 using the power generated by the renewable energy power generator 124 takes priority over the decrease in the power generated by the renewable energy power generator 124, making it possible to reduce the charging cost of the energy storage device 122.

[0209] The control method in this example of operation may include a step in which, during a period when the energy storage device 122 is not scheduled to be charged, and the suppression mode is not set, if the reverse power flow exceeds the upper limit, the power generated by the natural energy power generation device 124 is reduced without charging the energy storage device 122, thereby reducing the reverse power flow.

[0210] This control method performs the processing shown in example 1 in step S40. Then, even if the suppression mode is not set during a period when the energy storage device 122 is not scheduled to be charged, if the reverse power flow is greater than the upper limit, this control method reduces the power generated by the natural energy power generation device 124, as shown in step S44.

[0211] As a result, the amount of power generated and flowing back from the renewable energy power generation device 124 to the power grid 300 decreases, thus reducing the reverse power flow. Consequently, the reverse power flow becomes less likely to exceed the upper limit.

[0212] The control method in this example of operation may include a step of reducing the power generated by the renewable energy power generation device 124 to reduce the reverse power flow if the reverse power flow is greater than the upper limit even after charging the energy storage device 122.

[0213] In this control method, for example, if the reverse power flow is greater than the upper limit even after performing the processing of Operation Example 1 in step S40 and charging the energy storage device 122 as shown in step S14 of Operation Example 1, the power generated by the natural energy power generation device 124 is reduced as shown in step S44.

[0214] As a result, the amount of power generated and flowing back from the renewable energy power generation device 124 to the power grid 300 decreases, thus reducing the reverse power flow. Consequently, the reverse power flow becomes less likely to exceed the upper limit.

[0215] In this way, a control method and control device 110 that suppress the occurrence of problems caused by reverse power flow are realized.

[0216] As mentioned above, site 120 may be equipped with multiple energy storage devices 122. In this case, for example, in step S40, the controller 111 may execute an operating mode for each of the multiple energy storage devices 122.

[0217] [Another second example of operation example 5] Figure 7C is a flowchart of another second example of operation example 5 performed by the control device 110 according to this embodiment.

[0218] Another example of operation example 5 is an operation performed when the electric vehicle V is being charged by the charger 121.

[0219] First, the controller 111 executes the operating mode of the energy storage device 122 (S40).

[0220] The controller 111 then determines whether the reverse power flow from site 120 to power system 300 is greater than the upper limit (S10).

[0221] If the reverse power flow exceeds the upper limit (Yes in S10), the controller 111 controls the charging power of the charger 121 to increase (S42).

[0222] Furthermore, if the reverse power flow does not exceed the upper limit (No in S10), the operation will terminate.

[0223] The control method in this example of operation may include a step of increasing the charging power of the charger 121 to reduce the reverse power flow if the reverse power flow is greater than the upper limit even after reducing the discharge power of the energy storage device 122.

[0224] In this control method, for example, if the process of operation example 4 is performed in step S40, and the discharge power of the energy storage device 122 is reduced as shown in step S34 of operation example 4, but the reverse power flow is greater than the upper limit, the charging power of the charger 121 is increased as shown in step S42.

[0225] As a result, the power consumed by the charger 121 increases, that is, the power consumed within site 120 increases, which reduces the reverse power flow from site 120 to the power system 300. Consequently, the reverse power flow becomes less likely to exceed the upper limit. Furthermore, as a control measure to reduce the reverse power flow, the reduction in the discharge power of the energy storage device 122 takes precedence over the increase in the charging power of the charger 121, thus suppressing the degradation of the battery in the electric vehicle V that occurs with an increase in the charging power of the charger 121.

[0226] In this example of operation, when the suppression mode is not set, if the reverse power flow exceeds the upper limit during the planned discharge period of the energy storage device 122, the charging power of the charger 121 is increased without reducing the discharge power of the energy storage device 122 to reduce the reverse power flow.

[0227] This control method, for example, performs the processing shown in operation example 4 in step S40. Then, when the suppression mode is not set, if the reverse power flow is greater than the upper limit during the planned discharge period of the energy storage device 122, this control method increases the charging power of the charger 121, as shown in step S42 of Figure 7C.

[0228] As a result, the power consumed by the charger 121 increases, that is, the power consumed within site 120 increases, which reduces the reverse power flow from site 120 to the power grid 300. Consequently, the reverse power flow becomes less likely to exceed the upper limit.

[0229] The control method in this example of operation may include a step of increasing the charging power of the charger 121 to reduce the reverse power flow if the reverse power flow is greater than the upper limit even after charging the energy storage device 122.

[0230] In this control method, for example, in step S40, the suppression mode of step S24 of the process in operation example 4 is executed. In this suppression mode, if the reverse power flow is greater than the upper limit even when the energy storage device 122 is charged, the charging power of the charger 121 is increased as shown in step S42.

[0231] As a result, the power consumed by the charger 121 increases, that is, the power consumed within site 120 increases, which reduces the reverse power flow from site 120 to the power system 300. Consequently, the reverse power flow becomes less likely to exceed the upper limit. Furthermore, as a control measure to reduce the reverse power flow, charging of the energy storage device 122 is prioritized over increasing the charging power of the charger 121, thus suppressing the deterioration of the battery in the electric vehicle V that occurs with an increase in the charging power of the charger 121.

[0232] In the control method described in this example, if the reverse power flow exceeds the upper limit during the planned charging period of the energy storage device 122, while the suppression mode is not set, the charging power of the charger 121 may be increased to reduce the reverse power flow without reducing the charging power of the energy storage device 122.

[0233] This control method, for example, performs the processing shown in Operation Example 2 in step S40. Then, in this control method, if the reverse power flow is greater than the upper limit while the suppression mode is not set during the planned charging period of the energy storage device 122, the charging power of the charger 121 is increased as shown in step S42.

[0234] As a result, the power consumed by the charger 121 increases, that is, the power consumed within site 120 increases, which reduces the reverse power flow from site 120 to the power grid 300. Consequently, the reverse power flow becomes less likely to exceed the upper limit.

[0235] The control method in this example of operation may include a step of increasing the charging power of the charger 121 to reduce the reverse power flow if the reverse power flow is greater than the upper limit even when the charging power of the energy storage device 122 is increased.

[0236] In this control method, for example, if the process of operation example 3 is performed in step S40, and the charging power of the energy storage device 122 is increased as shown in step S14 of operation example 3, but the reverse power flow is greater than the upper limit, the charging power of the charger 121 is increased as shown in step S42.

[0237] As a result, the power consumed by the charger 121 increases, that is, the power consumed within site 120 increases, which reduces the reverse power flow from site 120 to the power system 300. Consequently, the reverse power flow becomes less likely to exceed the upper limit. Furthermore, as a control measure to reduce the reverse power flow, the increase in the charging power of the energy storage device 122 is prioritized over the increase in the charging power of the charger 121, thus suppressing the degradation of the battery in the electric vehicle V that occurs with an increase in the charging power of the charger 121.

[0238] The control method in this example of operation may include a step in which, during a period when the energy storage device 122 is not scheduled to be charged, and the suppression mode is not set, if the reverse power flow exceeds the upper limit, the charging power of the charger 121 is increased without charging the energy storage device 122 to reduce the reverse power flow.

[0239] This control method, for example, performs the processing shown in Operation Example 1 in step S40. Then, even if the suppression mode is not set during a period when the energy storage device 122 is not scheduled to be charged, if the reverse power flow is greater than the upper limit, this control method increases the charging power of the charger 121, as shown in step S42.

[0240] As a result, the power consumed by the charger 121 increases, that is, the power consumed within site 120 increases, which reduces the reverse power flow from site 120 to the power grid 300. Consequently, the reverse power flow becomes less likely to exceed the upper limit.

[0241] The control method in this example of operation may include a step of increasing the charging power of the charger 121 and reducing the reverse power flow if the reverse power flow is greater than the upper limit even after charging the energy storage device 122.

[0242] In this control method, for example, if the reverse power flow is greater than the upper limit even after performing the process of operation example 1 in step S40 and charging the energy storage device 122 as shown in step S14 of operation example 1, the charging power of the charger 121 is increased as shown in step S42.

[0243] As a result, the power consumed by the charger 121 increases, that is, the power consumed within site 120 increases, which reduces the reverse power flow from site 120 to the power grid 300. Consequently, the reverse power flow becomes less likely to exceed the upper limit.

[0244] In this way, a control method and control device 110 that suppress the occurrence of problems caused by reverse power flow are realized.

[0245] As mentioned above, site 120 may be equipped with multiple energy storage devices 122. In this case, for example, in step S40, the controller 111 may execute an operating mode for each of the multiple energy storage devices 122.

[0246] In the above operation examples 1 to 5, information indicating the reverse power flow stored in the memory 112 is acquired by the controller 111 at regular intervals, and each time this information is acquired, the reverse power flow stored in the memory 112 is updated. However, this is not the only example.

[0247] The controller 111 may acquire information indicating the predicted reverse power flow based on the power detected by the power meter 200 in the past at site 120. Figure 8 is a diagram showing the predicted power values ​​detected by the power meter 200 according to this embodiment.

[0248] Figure 8 shows the predicted value and upper limit of the power detected by the power meter 200. Figure 8 is a diagram showing the predicted fluctuation of power detected by the power meter 200 within a given day. The power detected by the power meter 200 shown in Figure 8 is predicted based on the average value of the power over a predetermined period of several days to several tens of days. Figure 8 also shows the upper limit. This upper limit may be the upper limit for the first example or the upper limit for the second example described above.

[0249] In Figure 8, the vertical axis represents the power supplied to site 120. In other words, in Figure 8, the larger the reverse power flow, the more negative the value on the vertical axis. Therefore, Figure 8 indicates that reverse power flow is occurring when the predicted power value detected by the power meter 200 is less than 0 kW. Furthermore, when the predicted power value detected by the power meter 200 is less than the upper limit, it corresponds to when the reverse power flow is greater than the upper limit.

[0250] The controller 111 controls the charging or discharging power of the energy storage device 122 when the reverse power flow exceeds the upper limit. More specifically, the controller 111 decides before the start of a certain day shown in Figure 8 to control the charging or discharging power of the energy storage device 122 to reduce the reverse power flow at the time 12:00 when the reverse power flow exceeds the upper limit shown in Figure 8. Then, at 12:00 on a certain day shown in Figure 8, the controller 111 controls the charging or discharging power of the energy storage device 122.

[0251] In other words, in the above operation examples 1 to 5, the controller 111 may determine whether the reverse power flow is greater than the upper limit each time information indicating the reverse power flow is acquired. However, as explained with reference to Figure 8, the controller 111 may determine in advance whether the reverse power flow is greater than the upper limit and control the charging power or discharging power of the energy storage device 122 based on that result.

[0252] (Modifications) Modifications of the embodiment are described below. In the following, the differences from the embodiment will be the main focus of the explanation, and the explanation of the common points may be omitted or simplified.

[0253] In this modified example, the control system 100 according to the embodiment is used, which is common to the embodiment. However, in this modified example, as the suppression mode, operation example 6 is used instead of the processing from step S10 onwards in the processing of operation example 1 shown in Figure 3 according to the embodiment, and as the discharge mode, operation example 7 is used instead of operation example 4 shown in Figure 6 according to the embodiment.

[0254] Below, we will describe operation examples 6 and 7 related to the control method performed by the control device 110 according to this modified example.

[0255] [Operation Example 6] Figure 9 is a flowchart of Operation Example 6 performed by the control device 110 according to this modified example.

[0256] Operation example 6 is an operation performed when the electric vehicle V is being charged by the charger 121.

[0257] In operation example 6, the control system 100 is set to suppression mode, meaning Figure 9 is a flowchart showing the suppression mode in operation. Furthermore, the control system 100 may or may not have a charge mode set, and may or may not have a discharge mode set.

[0258] First, the controller 111 determines whether the reverse power flow from site 120 to power system 300 is greater than the upper limit (S10).

[0259] If the reverse power flow does not exceed the upper limit (No in S10), the operation terminates.

[0260] If the reverse power flow exceeds the upper limit (Yes in S10), the controller 111 determines whether the energy storage device 122 is discharging (S18). The controller 111 may also obtain information indicating whether the energy storage device 122 is discharging, which is output from the communication interface provided by the energy storage device 122. The controller 111 may then determine whether the energy storage device 122 is discharging based on the obtained information. When the energy storage device 122 is discharging, the information also indicates the discharge power of the energy storage device 122.

[0261] If the energy storage device 122 is discharging (Yes in S18), the controller 111 determines whether the discharge power of the energy storage device 122 is less than the excess amount, which is the amount by which the reverse power flow exceeds the upper limit (S32). Note that this discharge power of the energy storage device 122 is the discharge power of the energy storage device 122 indicated by the information indicating whether or not the energy storage device 122 is discharging. The controller 111 calculates the excess amount, which is the difference between the reverse power flow and the upper limit, compares the calculated excess amount with the discharge power of the energy storage device 122 indicated by the information, and performs the process in step S32.

[0262] If the discharge power of the energy storage device 122 is less than the excess amount (Yes in S32), the controller 111 controls the energy storage device 122 to stop discharging (S34). In this case, the discharge power of the energy storage device 122 becomes 0.

[0263] Furthermore, if the discharge power of the energy storage device 122 is greater than the excess amount (No in S32), the controller 111 controls the discharge power of the energy storage device 122 to decrease by the excess amount (S36).

[0264] After the processing in step S34, the processing in step S10 for the second time in operation example 6 is performed.

[0265] If the reverse power flow does not exceed the upper limit (resulting in a "No" in the second S10), the operation terminates.

[0266] If the reverse power flow exceeds the upper limit in the second step S10 (Yes in the second S10), the controller 111 determines whether the reverse power flow will exceed the upper limit even if the energy storage device 122 is charged at the maximum charging power (S12).

[0267] If the reverse power flow exceeds the upper limit even when the energy storage device 122 is charged at its maximum charging power (Yes in S12), the controller 111 controls the energy storage device 122 to charge at its maximum charging power (S14).

[0268] When the energy storage device 122 is charged at its maximum charging power, if the reverse power flow does not exceed the upper limit (No in S12), the controller 111 controls the energy storage device 122 to charge the excess amount (S16).

[0269] Furthermore, if the energy storage device 122 is not discharging (No in S18), the process in step S12 is performed.

[0270] [Operation Example 7] Figure 10 is a flowchart of Operation Example 7 performed by the control device 110 according to this modified example.

[0271] Operation Example 7 is an operation performed when the electric vehicle V is being charged by the charger 121. In Operation Example 7, the control system 100 is set to discharge mode, and therefore Figure 10 is a flowchart showing the execution of the discharge mode. The control system 100 may or may not be set to suppression mode.

[0272] The energy storage device 122 discharges at the planned discharge power (S330). For example, the controller 111 outputs information indicating the discharge power to be discharged by the energy storage device 122 via a communication interface, and the energy storage device 122 acquires the outputted information and discharges at the discharge power indicated in the acquired information. The information indicating the discharge power may be stored in the memory 112.

[0273] Furthermore, the controller 111 determines whether or not the control system 100 is set to suppression mode (S22).

[0274] If the suppression mode is set (Yes in S22), the controller 111 executes the suppression mode (S24). That is, the controller 111 performs the process shown in the operation example 6 in Figure 9.

[0275] Furthermore, if the suppression mode is not set (No in S22), the operation ends.

[0276] As described above, the suppression mode and discharge mode according to this modified example should be operated accordingly. Furthermore, the charging mode according to this modified example is the same as the charging mode shown in Operation Example 2 of the embodiment, except for the following one point. That point is that in step S24 of Operation Example 2 shown in Figure 4, the suppression mode shown in Figure 9 is performed. Note that the operation example in which the charging mode according to this modified example is performed may be referred to as Operation Example 8.

[0277] Furthermore, in this modified example, the operation shown in Operation Example 5 of the embodiment may be performed. In step S40 of Operation Example 5 shown in Figure 7A, one of the operations from Operation Example 6, Operation Example 7, and Operation Example 8 of this modified example may be performed, and then the first step S10 of Operation Example 5 may be performed. If the processing of another step S10 has been performed in the preceding step S40, this first step S10 processing may not be performed.

[0278] For example, the following actions should be performed.

[0279] In this example of operation, the control method utilizes the energy storage device 122, and when a suppression mode is set to keep the reverse power flow below an upper limit, if the reverse power flow exceeds the upper limit during the planned discharge period of the energy storage device 122, the discharge power of the energy storage device 122 is reduced to reduce the reverse power flow.

[0280] This control method, for example, performs the processing of operation example 7 in step S40. This control method reduces the discharge power of the energy storage device 122 when the suppression mode is set and the reverse power flow is greater than the upper limit during the planned discharge period of the energy storage device 122. An example of reducing the discharge power of the energy storage device 122 is the processing in step S34 or step S36 of operation example 6, which is performed in step S24 of Figure 10.

[0281] As a result, when the suppression mode is set and the reverse power flow is greater than the upper limit during the planned discharge period of the energy storage device 122, the discharge power flowing back from the energy storage device 122 to the power system 300 decreases, thus reducing the reverse power flow. Consequently, the reverse power flow becomes less likely to exceed the upper limit.

[0282] The control method relating to this example of operation may include a step in which, when a suppression mode is set to keep the reverse power flow below an upper limit using the energy storage device 122, if the reverse power flow is greater than the upper limit even when the discharge power of the energy storage device 122 is reduced, the energy storage device 122 is charged to reduce the reverse power flow.

[0283] This control method, for example, performs the processing shown in Operation Example 7 in step S40. With the suppression mode set, the controller 111 reduces the discharge power of the energy storage device 122. An example of reducing the discharge power of the energy storage device 122 is the processing in step S34 of Operation Example 6, which is performed in step S24 of Figure 10. If the reverse power flow is still greater than the upper limit even after the energy storage device 122 reduces its discharge power, the energy storage device 122 is charged by performing processing such as step S14.

[0284] As a result, charging power, which is the power consumed by the energy storage device 122, is generated, that is, the total power consumed within site 120 increases, and the reverse power flow decreases by the amount of charging power consumed by the energy storage device 122. As a result, the reverse power flow becomes less likely to exceed the upper limit.

[0285] In this way, a control method and control device 110 that suppress the occurrence of problems caused by reverse power flow are realized.

[0286] (Other Embodiments) Although embodiments of the control device 110 have been described above according to embodiments and modifications, embodiments of the control device 110 are not limited to embodiments and modifications. Modifications that a person skilled in the art can conceive of may be made to the embodiments and modifications, and multiple components in the embodiments and modifications may be combined arbitrarily.

[0287] The control device 110 may be installed within site 120, or it may be installed in a remote location away from site 120. If the control device 110 is installed in a remote location away from site 120, a relay device may be installed within site 120. The relay device may acquire information output from the control device 110 and control the energy storage device 122, etc., according to the acquired information.

[0288] Each operation example may be performed periodically, or it may be performed when the administrator of the control system 100 inputs predetermined information via the input interface and the controller 111 acquires the input predetermined information or acquires information from a connected device.

[0289] For example, in the embodiments and modifications, a process performed by a specific component may be performed by another component instead of that specific component. Furthermore, the order of multiple processes may be changed, or multiple processes may be executed in parallel. Also, the first and second ordinal numbers used in the description may be replaced, removed, or newly assigned as appropriate. These ordinal numbers do not necessarily correspond to a meaningful order and may be used for identifying elements.

[0290] Furthermore, the control method, which includes the steps performed by each component of the control device 110, may be executed by any system or device. In other words, this control method may be executed by the control device 110 described above, or by another system or device.

[0291] For example, part or all of the control method may be executed by a computer equipped with a processor, memory, and input / output circuits, etc. In this case, the control method may be executed by the computer executing a program that causes the computer to execute the control method.

[0292] Furthermore, the above program may be recorded on a non-temporary computer-readable recording medium such as a CD-ROM.

[0293] Furthermore, each component of the control device 110 may be made of dedicated hardware, general-purpose hardware that executes the above-mentioned program, or a combination of these. The general-purpose hardware may consist of a memory on which the program is stored, and a general-purpose processor that reads the program from the memory and executes it. Here, the memory may be semiconductor memory or a hard disk, and the general-purpose processor may be a CPU.

[0294] Furthermore, dedicated hardware may consist of memory and a dedicated processor, etc. For example, a dedicated processor may refer to memory and execute the control method described above.

[0295] Furthermore, each component of the control device 110 may be an electrical circuit. These electrical circuits may form a single electrical circuit as a whole, or they may be separate electrical circuits. Also, these electrical circuits may correspond to dedicated hardware, or they may correspond to general-purpose hardware that executes the above-mentioned program, etc.

[0296] This disclosure can be used as a control method or control device to suppress the occurrence of problems caused by reverse power flow.

[0297] 100 Control system 110 Control device 111 Controller 112 Memory device 120 Site 121 Charger 122 Energy storage device 123 Building 124 Renewable energy power generation device 200 Power meter 300 Power grid

Claims

1. A control method performed by a control device, wherein in a facility equipped with a charger for charging an electric vehicle, a power storage device, and a renewable energy power generation device, when the electric vehicle is being charged by the charger, if the reverse power flow from the facility to the power grid exceeds an upper limit, the control method includes the step of controlling the charging power or discharging power of the power storage device to reduce the reverse power flow.

2. The control method according to claim 1, wherein when the reverse power flow exceeds the upper limit, the discharge power of the energy storage device is reduced to reduce the reverse power flow.

3. The control method according to claim 2, wherein if the reverse power flow exceeds the upper limit during the planned discharge period of the energy storage device, the discharge power of the energy storage device is reduced to reduce the reverse power flow.

4. The control method according to claim 3, wherein, even when a suppression mode is not set to reduce the reverse power flow to below the upper limit using the energy storage device, if the reverse power flow exceeds the upper limit during the planned discharge period of the energy storage device, the discharge power of the energy storage device is reduced to reduce the reverse power flow.

5. The control method according to any one of claims 2 to 4, further comprising the step of reducing the power generation of the natural energy power generation device and reducing the reverse power flow if the reverse power flow is greater than the upper limit even after reducing the discharge power of the energy storage device.

6. The control method according to any one of claims 2 to 4, further comprising the step of increasing the charging power of the charger and reducing the reverse power if the reverse power flow is greater than the upper limit even when the discharge power of the energy storage device is reduced.

7. The control method according to claim 2, wherein, with a suppression mode set to keep the reverse power flow below the upper limit using the energy storage device, if the reverse power flow exceeds the upper limit during the planned discharge period of the energy storage device, the discharge power of the energy storage device is reduced to reduce the reverse power flow; and, with the suppression mode not set, if the reverse power flow exceeds the upper limit during the planned discharge period of the energy storage device, the discharge power of the energy storage device is not reduced, but the power generation of the natural energy power generation device is reduced to reduce the reverse power flow.

8. The control method according to claim 2, wherein, with a suppression mode set to keep the reverse power flow below the upper limit using the energy storage device, if the reverse power flow exceeds the upper limit during the planned discharge period of the energy storage device, the discharge power of the energy storage device is reduced to reduce the reverse power flow; and, with the suppression mode not set, if the reverse power flow exceeds the upper limit during the planned discharge period of the energy storage device, the discharge power of the energy storage device is not reduced, and the charging power of the charger is increased to reduce the reverse power flow.

9. The control method according to claim 2, 3, 7, or 8, further comprising the step of charging the energy storage device to reduce the reverse power flow if, while a suppression mode is set to reduce the reverse power flow to below the upper limit using the energy storage device, the discharge power of the energy storage device is reduced, and the reverse power flow is still greater than the upper limit.

10. The control method according to claim 9, further comprising the step of reducing the power output of the renewable energy power generation device to reduce the reverse power output if the reverse power output is greater than the upper limit even after charging the energy storage device.

11. The control method according to claim 9, further comprising the step of increasing the charging power of the charger to reduce the reverse power flow if the reverse power flow is greater than the upper limit even after charging the energy storage device.

12. The control method according to claim 1, wherein when the reverse power flow exceeds the upper limit, the charging power of the energy storage device is increased to reduce the reverse power flow.

13. The control method according to claim 12, wherein if the reverse power flow exceeds the upper limit during the planned charging period of the energy storage device, the charging power of the energy storage device is increased to reduce the reverse power flow.

14. The control method according to claim 13, wherein, even when a suppression mode is not set to reduce the reverse power flow to below the upper limit using the energy storage device, if the reverse power flow becomes greater than the upper limit during the planned charging period of the energy storage device, the charging power of the energy storage device is increased to reduce the reverse power flow.

15. The control method according to claim 13, wherein, during a planned charging period for the energy storage device, a suppression mode is set to use the energy storage device to keep the reverse power flow below the upper limit, and when the reverse power flow exceeds the upper limit, the charging power of the energy storage device is increased to reduce the reverse power flow; and during a planned charging period for the energy storage device, when the suppression mode is not set, and when the reverse power flow exceeds the upper limit, the charging power of the energy storage device is not reduced, but the power generated by the renewable energy power generation device is reduced to reduce the reverse power flow.

16. The control method according to claim 13, wherein, during a planned charging period for the energy storage device, a suppression mode is set to use the energy storage device to keep the reverse power flow below the upper limit, and when the reverse power flow exceeds the upper limit, the charging power of the energy storage device is increased to reduce the reverse power flow; and during a planned charging period for the energy storage device, when the suppression mode is not set, and when the reverse power flow exceeds the upper limit, the charging power of the charger is increased without reducing the charging power of the energy storage device to reduce the reverse power flow.

17. The control method according to any one of claims 12 to 16, further comprising the step of reducing the power output of the renewable energy power generation device to reduce the reverse power output if the reverse power output is greater than the upper limit even when the charging power of the energy storage device is increased.

18. The control method according to any one of claims 12 to 16, further comprising the step of increasing the charging power of the charger to reduce the reverse power flow if the reverse power flow is greater than the upper limit even when the charging power of the energy storage device is increased.

19. The control method according to claim 1, wherein when the reverse power flow exceeds the upper limit, the energy storage device is charged to reduce the reverse power flow.

20. The control method according to any one of claims 13, 14, and 19, wherein, during a period when the energy storage device is not scheduled to be charged, a suppression mode is set to use the energy storage device to reduce the reverse power flow to below the upper limit, and when the reverse power flow exceeds the upper limit, the energy storage device is charged to reduce the reverse power flow.

21. The control method according to claim 20, further comprising the step of reducing the power output of the renewable energy power generation device without charging the energy storage device if the reverse power flow exceeds the upper limit value during a period when the energy storage device is not scheduled for charging and the suppression mode is not set.

22. The control method according to claim 20, further comprising the step of reducing the reverse power flow by increasing the charging power of the charger without charging the energy storage device if the reverse power flow exceeds the upper limit value during a period when the energy storage device is not scheduled for charging and the suppression mode is not set.

23. The control method according to claim 19 or 20, further comprising the step of reducing the power output of the renewable energy power generation device and reducing the reverse power output if the reverse power flow is greater than the upper limit even after charging the energy storage device.

24. The control method according to claim 19 or 20, further comprising the step of increasing the charging power of the charger and reducing the reverse power if the reverse power flow is greater than the upper limit even after charging the energy storage device.

25. The control method according to any one of claims 6, 8, 11, 16, 18, 22, and 24, further comprising the step of reducing the power output of the natural energy power generation device and reducing the reverse power output if the reverse power output is greater than the upper limit even when the charging power of the charger is increased.

26. A control device comprising: a memory for storing reverse power flow from a facility equipped with a charger for charging electric vehicles, an energy storage device, and a renewable energy power generation device to the power grid; and a controller that, when the electric vehicle is being charged by the charger at the facility, and the reverse power flow from the facility to the power grid exceeds an upper limit, controls the charging power or discharging power of the energy storage device to reduce the reverse power flow.

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