Power conversion system

Abstract

To provide a power conversion system connected with a power storage unit capable of precisely measuring the amount of electricity output from the power conversion system according to its origin.SOLUTION: An AC power meter (14) is placed between an inverter (12) and a distribution board (3). A first DC power meter (151) is placed between a first DC / DC converter (11a) and a power generation unit (6). A second DC power meter (152) is placed between a second DC / DC converter (11b) and a stationary-type power storage unit (7). A control unit (13) is configured to measure the amount of power generated by the power generation unit (6) and output to the distribution board (3) based on the power measured by the AC power meter (14) and the first DC power meter (151)-the second DC power meter (152).SELECTED DRAWING: Figure 25

Description

[Technical field]

[0001] The present disclosure relates to a power conversion system to which a power storage unit is connected. [Background technology]

[0002] As of 2023, housing prices in Japan are soaring due to rising construction material costs and the weak yen. As a result, there are an increasing number of cases where PPA (Power Purchase Agreement) services, which do not require an initial investment, are being used to install solar power generation systems in order to realize ZEH (Zero Energy House). PPA services are structured so that the solar power generation system installed in a home or other building is owned by the PPA operator, and the contractor is charged for the solar power generation that is self-consumption. Maintenance of the solar power generation system is also carried out by the PPA operator. In recent years, there have been an increasing number of cases where major electric power companies are offering PPA services in order to lock in customers.

[0003] Previously, PPA operators installed smart meters between the power conditioner and the distribution board to measure the amount of electricity used for self-consumption billing. These smart meters needed to be replaced every 10 years, which was a burden for PPA operators. In April 2022, the Energy Supply Strengthening Act came into effect, allowing electricity trading using the power measurement results of power conditioners, which will reduce the burden on PPA operators.

[0004] As of 2023, grid electricity prices in Japan remain high due to rising resource prices and the weak yen, and the grid electricity price per kWh continues to exceed the selling price of solar power generation per kWh. The purchase price of solar power generation under the Feed-in Tariff (FIT) system has been declining year by year, and it is predicted that the selling price of solar power generation will continue to be lower than the grid electricity price in the future.

[0005] Therefore, there is an increasing need to store solar power generation electricity in storage batteries for self-consumption. Accordingly, systems that link solar power generation systems with storage systems (hereinafter, hybrid storage systems) are becoming more widespread (see, for example, Patent Document 1). PPA operators are also stepping up the rollout of hybrid storage systems to improve the economic value they provide to their contract holders. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2019-118209 A Summary of the Invention [Problem to be solved by the invention]

[0007] In a multi-input power conditioner, where a stationary storage battery or an on-board storage battery is connected to the input side in addition to solar cells, the origin of the electricity charged in the stationary storage battery or the on-board storage battery is unknown, so it was difficult to charge the output power of the multi-input power conditioner with a smart meter. As of 2023, PPA operators basically adopt a monthly flat-rate billing system. Many PPA operators want to shift from a monthly flat-rate billing system to a pay-as-you-go billing system. Therefore, there is a demand for highly accurate metering of the electricity actually consumed by the operator, which originates from renewable energy.

[0008] The present disclosure has been made in consideration of these circumstances, and its purpose is to provide a technology for measuring with high accuracy the amount of electricity of different origins output from a power conversion system connected to a power storage unit. [Means for solving the problem]

[0009] In order to solve the above problems, a power conversion system according to an embodiment of the present disclosure includes a first DC / DC converter connected to a power generation device that converts renewable energy into electrical energy, a second DC / DC converter connected to a fixed power storage unit, an inverter connected to a distribution board having a DC terminal side connected to a junction of the first DC / DC converter and the second DC / DC converter and an AC terminal side connected to a system and a load, an AC power meter installed between the inverter and the distribution board, a first DC power meter installed between the first DC / DC converter and the power generation device, a second DC power meter installed between the second DC / DC converter and the fixed power storage unit, and a control unit that measures the amount of power derived from the power generation device and output to the distribution board based on the power measured by the AC power meter and the first DC power meter-second DC power meter.

[0010] Any combination of the above components and conversion of the present disclosure into an apparatus, system, method, computer program, etc. are also valid aspects of the present disclosure. Effect of the Invention

[0011] According to the present disclosure, in a power conversion system connected to a power storage unit, the amount of power output from the power conversion system by source can be measured with high accuracy. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram showing a basic configuration of a tribrid energy storage system. [Diagram 2] This is a table showing the tolerance classes according to transaction size as indicated in the guidelines related to the specific metrology system. [Diagram 3] This is an explanatory diagram on the handling of apportionment metering under the specific measurement system, posted on the website of the Agency for Natural Resources and Energy. [Figure 4] FIG. 1 is a diagram showing the configuration of a tribrid energy storage system according to a comparative example that is equipped with a function for measuring the amount of electricity by source. [Diagram 5]This figure defines the power at each measurement point of the power conversion system shown in Figure 4 and the amount of power stored in the stationary storage battery by source. [Figure 6] FIG. 1 is a diagram showing a configuration of a tribrid energy storage system according to an embodiment, which is equipped with a function for measuring the amount of electricity by source. [Figure 7] This figure defines the power at each measurement point of the power conversion system shown in FIG. 6 and the amount of power stored in the stationary storage battery by source. [Figure 8] FIG. 11 is a graph showing combinations of power flow directions of a grid, a solar cell, a stationary storage battery, and an in-vehicle storage battery in the tribrid power storage system according to the embodiment. [Figure 9] FIG. 2 is a diagram illustrating the directions of currents in a grid, a solar cell, a stationary storage battery, and an in-vehicle storage battery in a first pattern in the tribrid power storage system according to the embodiment. [Figure 10] FIG. 11 is a diagram showing a graph summarizing a calculation algorithm for source-specific power values ​​in a first pattern in the tribrid power storage system according to the embodiment. [Figure 11] FIG. 11 is a diagram illustrating the directions of currents in the grid, solar cells, stationary storage batteries, and vehicle-mounted storage batteries in a second pattern in the tribrid power storage system according to the embodiment. [Figure 12] FIG. 13 is a graph showing a summary of a calculation algorithm for source-specific power values ​​in a second pattern in the tribrid power storage system according to the embodiment. [Figure 13] FIG. 13 is a diagram illustrating the directions of currents in the grid, solar cells, stationary storage batteries, and vehicle-mounted storage batteries in a third pattern in the tribrid power storage system according to the embodiment. [Figure 14] FIG. 13 is a graph showing a summary of a calculation algorithm for source-specific power values ​​in a third pattern in the tribrid power storage system according to the embodiment. [Figure 15] FIG. 13 is a diagram illustrating the directions of currents in the grid, solar cells, stationary storage batteries, and vehicle-mounted storage batteries in a fourth pattern in the tribrid power storage system according to the embodiment. [Figure 16] FIG. 13 is a graph showing a summary of a calculation algorithm for source-specific power values ​​in a fourth pattern in the tribrid power storage system according to the embodiment. [Figure 17] FIG. 13 is a diagram illustrating the directions of currents in the grid, solar cells, stationary storage batteries, and vehicle-mounted storage batteries in a fifth pattern in the tribrid power storage system according to the embodiment. [Figure 18] FIG. 13 is a graph showing a summary of a calculation algorithm for source-specific power values ​​in a fifth pattern in the tribrid power storage system according to the embodiment. [Figure 19] FIG. 13 is a diagram illustrating the directions of currents in the grid, solar cells, stationary storage batteries, and vehicle-mounted storage batteries in a sixth pattern in the tribrid power storage system according to the embodiment. [Figure 20] FIG. 13 is a graph showing a summary of a calculation algorithm for source-specific power values ​​in a sixth pattern in the tribrid power storage system according to the embodiment. [Figure 21] FIG. 13 is a diagram illustrating the directions of currents in the grid, solar cells, stationary storage batteries, and vehicle-mounted storage batteries in a seventh pattern in the tribrid power storage system according to the embodiment. [Figure 22] FIG. 13 is a graph showing a summary of a calculation algorithm for source-specific power values ​​in a seventh pattern in the tribrid power storage system according to the embodiment. [Diagram 23] FIG. 13 is a diagram illustrating the directions of currents in the grid, solar cells, stationary storage batteries, and vehicle-mounted storage batteries in an eighth pattern in the tribrid power storage system according to the embodiment. [Figure 24] FIG. 13 is a graph showing a summary of a calculation algorithm for source-specific power values ​​in an eighth pattern in the tribrid power storage system according to the embodiment. [Diagram 25] 1 is a diagram showing a configuration of a hybrid power storage system according to an embodiment, which is equipped with a function for measuring the amount of power according to its origin. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] 1 is a diagram showing the basic configuration of a tribrid energy storage system, which is also called a V2H energy storage system, in which a solar cell 6, a stationary storage battery 7, and an in-vehicle storage battery 8 are connected to a power conversion system 1.

[0014] The power conversion system 1 includes an inverter 12, a first DC / DC converter 11a, a second DC / DC converter 11b, a third DC / DC converter 11c, and a control unit 13. The power conversion system 1 is a power conditioner linked to a storage battery. The second DC / DC converter 11b is a charge / discharge converter for the stationary storage battery 7, and may be built into the power conditioner or may be externally attached to the DC bus Bd of the power conditioner. The third DC / DC converter 11c is a V2H converter for the vehicle-mounted storage battery 8, and may be built into the power conditioner or may be externally attached to the DC bus Bd of the power conditioner.

[0015] The solar cell 6 can directly convert light energy into DC power by utilizing the photovoltaic effect. As the solar cell 6, a silicon solar cell, a solar cell made of a material such as a compound semiconductor, a dye-sensitized solar cell, an organic thin-film solar cell, or the like is used. The solar cell 6 is connected to a first DC / DC converter 11a and outputs the generated power to the first DC / DC converter 11a. The first DC / DC converter 11a is connected between the solar cell 6 and the DC bus Bd and is a converter capable of adjusting the voltage of the DC power output from the solar cell 6. The first DC / DC converter 11a can be configured, for example, by a boost chopper.

[0016] The stationary storage battery 7 is capable of charging and discharging power, and is composed of a lithium ion battery, a nickel metal hydride battery, etc. The stationary storage battery 7 is connected to the second DC / DC converter 11b, and charging and discharging of the stationary storage battery 7 is controlled by the second DC / DC converter 11b. The second DC / DC converter 11b is a bidirectional DC / DC converter connected between the stationary storage battery 7 and the DC bus Bd, and charges and discharges the stationary storage battery 7.

[0017] The on-board storage battery 8 is a drive storage battery mounted on the electric vehicle, and is composed of a lithium-ion storage battery, a nickel-metal hydride storage battery, or the like. The electric vehicle and the power conversion system 1 are connected by a charging cable. The on-board storage battery 8 is connected to the third DC / DC converter 11c when the electric vehicle is parked at home, and charging and discharging of the on-board storage battery 8 are controlled by the third DC / DC converter 11c. The third DC / DC converter 11c is a bidirectional DC / DC converter that is connected between the on-board storage battery 8 and the DC bus Bd, and charges and discharges the on-board storage battery 8 when the electric vehicle is parked at home.

[0018] The stationary or vehicle-mounted storage battery may be substituted with a supercapacitor such as an electric double layer capacitor or a lithium ion capacitor. In this specification, the storage battery and the capacitor are collectively referred to as the power storage unit.

[0019] The inverter 12 has a DC terminal connected to the DC bus Bd and an AC terminal connected to the distribution board 3. The first DC / DC converter 11a to the third DC / DC converter 11c are connected in parallel to the DC bus Bd. The inverter 12 converts DC power input from at least one of the first DC / DC converter 11a, the second DC / DC converter 11b, and the third DC / DC converter 11c via the DC bus Bd into AC power, and outputs the converted AC power to the distribution board 3. At that time, the inverter 12 can control the voltage or current of the AC power to be output.

[0020] The inverter 12 can also convert AC power supplied from a commercial power system 2 (hereinafter simply referred to as system 2) via the distribution board 3 into DC power and output the converted DC power to the DC bus Bd. The distribution board 3 is connected to the system 2 and a home load 4. The home load 4 is a general term for loads installed in the home.

[0021] It is desirable to use converters having the same or as close conversion efficiency as possible for the first DC / DC converter 11a to the third DC / DC converter 11c and the inverter 12. It is also desirable to use converters having as high efficiency as possible.

[0022] The control unit 13 controls the entire power conversion system 1. The control unit 13 can be realized by a combination of hardware resources and software resources, or by hardware resources alone. As hardware resources, analog circuits, logic circuits, microcontrollers, DSPs, ROMs, RAMs, ASICs, FPGAs, and other LSIs can be used. As software resources, programs such as firmware can be used.

[0023] The control unit 13 executes MPPT (Maximum Power Point Tracking) control of the solar cell 6 by controlling the first DC / DC converter 11a. Specifically, the control unit 13 measures the input voltage and input current of the first DC / DC converter 11a, which are the output voltage and output current of the solar cell 6, to estimate the power generated by the solar cell 6. The control unit 13 generates a voltage command value for making the power generated by the solar cell 6 a maximum power point (optimum operating point) based on the measured output voltage of the solar cell 6 and the estimated power generation. For example, the control unit 13 changes the operating point voltage by a predetermined step width according to a hill-climbing method to search for the maximum power point, and generates a voltage command value to maintain the maximum power point. The first DC / DC converter 11a performs switching operation in response to a drive signal based on the generated voltage command value.

[0024] The control unit 13 controls the second DC / DC converter 11b to control charging and discharging of the stationary storage battery 7. The second DC / DC converter 11b performs constant current (CC) discharge, constant voltage (CV) discharge, constant current charging, or constant voltage charging of the stationary storage battery 7 based on a current command value or a voltage command value set by the control unit 13. When the stationary storage battery 7 is operated to follow at least one of the power generation amount of the solar cell 6 and the power consumption amount of the domestic load 4, the control unit 13 generates a current command value for the second DC / DC converter 11b according to the voltage of the DC bus Bd.

[0025] The control unit 13 controls the third DC / DC converter 11c to control charging and discharging of the in-vehicle storage battery 8. The control unit 13 can communicate with a BMU (Battery Management Unit) of the in-vehicle storage battery 8 via a communication line in the charging cable. In the case of CHAdeMO (registered trademark), they are connected via a Controller Area Network (CAN). The third DC / DC converter 11c performs constant current discharge, constant voltage discharge, constant current charging, or constant voltage charging of the in-vehicle storage battery 8 based on a current command value or a voltage command value set by the control unit 13 or the BMU of the in-vehicle storage battery 8.

[0026] The control unit 13 controls the inverter 12 so that the voltage of the DC bus Bd maintains a target value. Specifically, the control unit 13 measures the voltage of the DC bus Bd and generates a current command value for matching the measured bus voltage with the target value. When the voltage of the DC bus Bd is higher than the target value, the control unit 13 generates a current command value for increasing the output power of the inverter 12, and when the voltage of the DC bus Bd is lower than the target value, the control unit 13 generates a current command value for decreasing the output power of the inverter 12. The inverter 12 performs a switching operation in response to a drive signal based on the generated current command value.

[0027] A smart meter 5 is connected between the grid 2 and the distribution board 3. The smart meter 5 is equipped with a voltage sensor and a current sensor, and measures power by multiplying the grid voltage measured by the voltage sensor by the current measured by the current sensor. The smart meter 5 can measure the integrated power amount for each specified period of time (e.g., 30 minutes). It can measure both forward flow power and reverse flow power. The integrated power amount measured by the smart meter 5 is used as basic data for calculating electricity charges by retail electricity suppliers. It is also used as basic data for calculations when selling solar power generated to power companies and aggregators.

[0028] Before the Energy Supply Resilience Act came into effect in April 2022, a PPA operator had to install a separate smart meter 5a for the PPA operator between the power conversion system 1 and the distribution board 3 in order to bill a contractant for the amount of electricity consumed by the home load 4. The smart meter 5a is equipped with a communication function and can transmit the accumulated amount of electricity to the PPA operator server 10 via the network 9 at predetermined intervals (e.g., 30 minutes). Although not shown in FIG. 1, the smart meter 5 installed between the grid 2 and the distribution board 3 can also transmit the accumulated amount of electricity to the retail electricity operator server via the network 9 at predetermined intervals.

[0029] After the Energy Supply Resilience Act comes into effect in April 2022, instead of installing a smart meter 5a between the power conversion system 1 and the distribution board 3, it will be permitted to use the amount of electricity measured by a power conditioner that meets the conditions set forth in the guidelines for the specific measurement system as the basic data for calculating electricity charges.

[0030] The guidelines for the specified measurement system issued by the Agency for Natural Resources and Energy in April 2022 state with regard to the separation of electricity origin from multi-input power conditioners that "if the impact of apportioned metering can be limited by innovating the apportionment method, etc., the impact can be explained to the other party to the transaction related to specified metering, and if the impact is not inferior to the accuracy permitted by specified metering, it can be subject to this system."

[0031] Figure 2 shows a table of tolerance classes according to transaction size, as shown in the guidelines for the specified metrology system. The guidelines state, "In principle, when a notifier selects a tolerance (note) for specified metrology according to the transaction size, the notifier should select it from range A in the table and conduct transactions, etc. If the notifier selects a tolerance in range B in the table and conducts transactions, etc., the notifier must fulfill its responsibility to explain more carefully than when specified metrology is conducted within range A, such as by explaining to the other party of the specified metrology transaction the specific impact (e.g., amount) of the error of the electric meter on the transaction, etc.," and "(Note) Tolerance refers to the allowable difference expressed in the absolute value of the error (the ratio of the true value to the measured value minus the true value). In this guideline, the tolerance refers to the allowable difference of the lead scale error. (The lead scale error is the idea of ​​the percentage of error from the indicated value, regardless of the magnitude of the measured value.)"

[0032] The guidelines also state, "Under this system, the tolerances that can be selected by the notifier during pre-use inspection, etc. are divided into seven levels, from 0.5 to 8.0%, and the tolerances during use are 0.9 to 10%, and the notifier can select which level to use depending on the scale of the transaction and conduct the transaction, etc. Electrical meters with larger errors than this cannot be used for specific metrology."

[0033] The n3 class (with a tolerance of 3.0% during use) is equivalent to the tolerance of a general smart meter. The n2 class (with a tolerance of 1.7% during use) is equivalent to the tolerance of a high-precision smart meter.

[0034] Figure 3 is an explanatory diagram on the handling of apportionment metering under the specified measurement system, posted on the website of the Agency for Natural Resources and Energy. The website of the Agency for Natural Resources and Energy states, "As shown in the above figure, when a certified specified measuring instrument, an electric power meter, is installed, and the amount of generated electricity from G1 = meter M x meter m1 / (meter m1 + meter m2) and the amount of generated electricity from G2 = meter M x meter m2 / (meter m1 + meter m2) are apportioned and traded, if the following conditions are met, the obligation to make efforts regarding accurate measurement required by the Measurement Act is fulfilled, and apportionment metering can be properly performed." The necessary conditions for fulfilling the obligation to make efforts for accurate measurement are stated to be (1) the timing of meter reading for each measuring instrument must be synchronized, and (2) the wiring must be capable of performing apportionment metering properly.

[0035] In the configuration shown in FIG. When the tolerance of meter M = 3%, the tolerance of meter m1 = 3%, and the tolerance of meter m2 = 3%, the tolerance of the amount of energy derived from G1 and the tolerance of the amount of energy derived from G2 will each be 3%. When the tolerance of meter M = 3%, the tolerance of meter m1 = -3%, and the tolerance of meter m2 = -3%, the tolerance of the amount of energy derived from G1 and the tolerance of the amount of energy derived from G2 will each be 3%. When the tolerance of meter M = 3%, the tolerance of meter m1 = 3%, and the tolerance of meter m2 = -3%, the tolerance of the amount of energy derived from G1 is -3% to 3%, and the tolerance of the amount of energy derived from G2 is 3% to 9.37%. The tolerance of the amount of energy derived from G2 is 3% when the ratio of the amount of energy derived from G1 is maximum, and 9.37% when the ratio of the amount of energy derived from G1 is minimum. When the tolerance of meter M = 3%, the tolerance of meter m1 = -3%, and the tolerance of meter m2 = 3%, the tolerance of the amount of energy derived from G1 is 3% to 9.37%, and the tolerance of the amount of energy derived from G2 is -3% to 3%. The tolerance of the amount of energy derived from G1 is 9.37% when the ratio of the amount of energy derived from G1 is maximum, and 3% when the ratio of the amount of energy derived from G1 is minimum.

[0036] Below, we will explain how to measure the amount of electricity by source using the apportionment metering method shown in Figure 3.

[0037] 4 is a diagram showing the configuration of a tribrid energy storage system according to a comparative example equipped with a function for measuring the amount of power by source. To precisely measure DC power in a multi-input power conversion system 1, it is necessary to take into account the conversion losses of each of the inverter 12, the first DC / DC converter 11a, the second DC / DC converter 11b, and the third DC / DC converter 11c.

[0038] In the comparative example shown in FIG. 4, measurement points are set before and after each of the inverter 12, the first DC / DC converter 11a, the second DC / DC converter 11b and the third DC / DC converter 11c in order to prevent a change in the proportion of the electric power-derived components and to absorb the above-mentioned conversion loss.

[0039] The AC power meter 14 is installed between the inverter 12 and the distribution board 3. The first DC power meter 151 is installed between the first DC / DC converter 11a and the solar cell 6. The second DC power meter 152 is installed between the second DC / DC converter 11b and the stationary storage battery 7. The third DC power meter 153 is installed between the third DC / DC converter 11c and the vehicle storage battery 8. The fourth DC power meter 154 is installed between the junction N1 of the DC bus Bd and the first DC / DC converter 11a. The fifth DC power meter 155 is installed between the junction N1 of the DC bus Bd and the second DC / DC converter 11b. The sixth DC power meter 156 is installed between the junction N1 of the DC bus Bd and the third DC / DC converter 11c. The seventh DC power meter 157 is installed between the inverter 12 and the junction N1 of the DC bus Bd.

[0040] The AC power meter 14 and the first DC power meter 151 to the seventh DC power meter 157 each include a voltage sensor and a current sensor. A power value is obtained by multiplying a voltage value measured by the voltage sensor by a current value measured by the current sensor. The voltage sensor and the current sensor used for metering to bill electricity charges and the voltage sensor and the current sensor used for controlling the inverter 12 and the DC / DC converters 11a to 11c are basically installed separately, but some of them may be shared. The AC power meter 14 and the first DC power meter 151 to the seventh DC power meter 157 are each designed to meet the requirements of a specified meter that falls within the tolerance of the n2 or n3 class shown in FIG. 2. In the tribrid energy storage system shown in FIG. 4, the smart meter 5a between the power conversion system 1 and the distribution board 3 shown in FIG. 1 is omitted.

[0041] The control unit 13 can calculate the power value according to the origin of each measurement point based on the power measured by the AC power meter 14 and each of the first to seventh DC power meter 151 to 157. The control unit 13 can ultimately measure the amount of power originating from the solar cell 6 output from the power conversion system 1 to the distribution board 3. The power at each measurement point is defined below.

[0042] FIG. 5 is a diagram that defines the power at each measurement point of the power conversion system 1 shown in FIG. 4 and the amount of power stored in the stationary storage battery 7 by origin. The origin of the amount of power (remaining capacity) stored in the stationary storage battery 7 is classified into the solar cell 6 (PV), the grid 2, and others. The others are the amount of power charged from the vehicle-mounted storage battery 8. The amount of power stored in the vehicle-mounted storage battery 8 may include power charged from a charger installed outside while the electric vehicle is out. Since it is difficult to strictly manage the origin of the amount of power stored in the vehicle-mounted storage battery 8, the origin of the amount of power stored in the vehicle-mounted storage battery 8 is not classified, and all of it is classified as others. Therefore, the power charged from the solar cell 6 to the vehicle-mounted storage battery 8 and discharged from the vehicle-mounted storage battery 8 and consumed in-house is excluded from the subject of the bill.

[0043] (1) Reverse flow power The power output from distribution board 3 to grid 2 measured by smart meter 5. (2) Forward flow power The power output from grid 2 to distribution board 3 measured by smart meter 5. (3) AC output power The power output from the power conversion system 1 to the distribution board 3 measured by the AC power meter 14. (4) AC input power The power input from the distribution board 3 to the power conversion system 1 measured by the AC power meter 14. (5) Bus output power The power output from the junction N1 of the DC bus Bd to the inverter 12 measured by the seventh DC power meter 157. (6) Bus input power The power input from the inverter 12 to the junction N1 of the DC bus Bd measured by the seventh DC power meter 157. (7) Power generated by PV bus The power output from the first DC / DC converter 11a to the junction N1 of the DC bus Bd, measured by the fourth DC power meter 154. (8)PV power generation The power output from the solar cell 6 to the first DC / DC converter 11a measured by the first DC power meter 151. (9)SB bus discharge power The power output from the second DC / DC converter 11b to the junction N1 of the DC bus Bd, measured by the fifth DC power meter 155. (10)SB bus charging power The power output from the junction N1 of the DC bus Bd to the second DC / DC converter 11b, measured by the fifth DC power meter 155. (11)SB discharge power The power output from the stationary storage battery 7 to the second DC / DC converter 11b, measured by the second DC power meter 152. (12)SB charging power The power output from the second DC / DC converter 11b to the stationary storage battery 7, measured by the second DC power meter 152. (13) EV bus discharge power The power output from the third DC / DC converter 11c to the junction N1 of the DC bus Bd, measured by the sixth DC power meter 156. (14) EV bus charging power The power output from the junction N1 of the DC bus Bd to the third DC / DC converter 11c, measured by the sixth DC power meter 156. (15)EV discharge power The power output from the vehicle-mounted storage battery 8 to the third DC / DC converter 11c, measured by the third DC power meter 153. (16)EV charging power The power output from the third DC / DC converter 11c to the vehicle-mounted storage battery 8, measured by the third DC power meter 153. (17) Amount of PV-derived electricity stored in stationary storage battery 7 (18) Amount of grid-derived electricity stored in stationary battery 7 (19) Amount of electricity of other origins stored in the stationary storage battery 7

[0044] Fig. 6 is a diagram showing the configuration of a tribrid energy storage system according to an embodiment equipped with a function for measuring the amount of electricity by source. In the tribrid energy storage system shown in Fig. 6, the fourth DC power meter 154 to the seventh DC power meter 157 of the tribrid energy storage system shown in Fig. 4 are omitted in order to reduce costs.

[0045] Fig. 7 is a diagram defining the power at each measurement point of the power conversion system 1 shown in Fig. 6 and the amount of power by source stored in the stationary storage battery 7. In the embodiment, (5) bus output power, (6) bus input power, (7) PV bus generated power, (9) SB bus discharge power, (10) SB bus charging power, (13) EV bus discharging power, and (14) EV bus charging power defined in the comparative example are not used.

[0046] For (3) AC output power, (11) SB discharge power, (12) SB charging power, and (16) EV charging power, it is also defined whether the power comes from PV, the grid, or other sources.

[0047] (3)_PV AC output power from PV The power derived from the solar cell 6 and output from the power conversion system 1 to the distribution board 3 as measured by the AC power meter 14. (3)_Grid AC output power derived from the grid The power derived from system 2 and output from power conversion system 1 to distribution board 3 as measured by AC power meter 14. (3)_Other AC output power from other sources Other power sources being output from the power conversion system 1 to the distribution board 3 as measured by the AC power meter 14. (11)_PV SB discharge power from PV The power derived from the solar cell 6 and output from the stationary storage battery 7 to the second DC / DC converter 11b, measured by the second DC power meter 152. (11)_Grid SB discharge power from grid The power derived from the system 2 and output from the stationary storage battery 7 to the second DC / DC converter 11b, measured by the second DC power meter 152. (11)_Others Other sources of SB discharge power The power of other origin that is output from the stationary storage battery 7 to the second DC / DC converter 11b and is measured by the second DC power meter 152. (12)_PV SB charging power from PV The power derived from the solar cell 6 and output from the second DC / DC converter 11b to the stationary storage battery 7, measured by the second DC power meter 152. (12)_Grid SB charging power from the grid The power derived from the system 2 and output from the second DC / DC converter 11b to the stationary storage battery 7, measured by the second DC power meter 152. (12)_Other SB charging power from other sources The power of other origin that is output from the second DC / DC converter 11b to the stationary storage battery 7 and that is measured by the second DC power meter 152. (16)_PV EV charging power from PV The power derived from the solar cell 6 and output from the third DC / DC converter 11c to the vehicle-mounted storage battery 8, measured by the third DC power meter 153. (16)_Grid EV charging power from the grid The power derived from the system 2 and output from the third DC / DC converter 11c to the vehicle storage battery 8, measured by the third DC power meter 153. (16)_Other EV charging power from other sources The power of other origins that is output from the third DC / DC converter 11c to the vehicle-mounted storage battery 8 and is measured by the third DC power meter 153.

[0048] (4) The origin of the AC input power is fixed to Grid 2. (8) The origin of the PV generation power is fixed to Solar Cell 6. (15) The origin of the EV discharge power is fixed to Other.

[0049] (4) AC input power, (8) PV power generation, (11) SB discharge power, and (15) EV discharge power are mixed on the DC bus Bd, but the component ratio of the DC bus Bd is considered to be the ratio of the amount of power injected. (3) AC output power, (11) SB discharge power, (12) SB charging power, and (16) EV charging power are each apportioned and separated using the ratio of the amount of power injected into the DC bus Bd.

[0050] (17) The amount of PV-derived electricity stored in the stationary storage battery 7, (18) the amount of grid-derived electricity stored in the stationary storage battery 7, and (19) the amount of other-derived electricity stored in the stationary storage battery 7 are considered as the remaining capacity actually stored at each point in time, rather than as an accumulated value.

[0051] The inverter 12, the second DC / DC converter 11b, and the third DC / DC converter 11c are assumed to operate in only one direction at each time point. Even if the stationary storage battery 7 or the vehicle-mounted storage battery 8 self-discharges, the ratio of the derived component of the amount of electric power is assumed to remain unchanged.

[0052] FIG. 8 is a diagram showing a graph summarizing combinations of power flow directions of the grid 2, solar cell 6, stationary storage battery 7, and vehicle-mounted storage battery 8 in the tribrid energy storage system according to the embodiment. The power flow direction of the grid 2 includes output ((3) AC output power) and input ((4) AC input power), and can be identified by the direction of power (direction of current) measured by the AC power meter 14. The power flow direction of the solar cell 6 is fixed as power generation ((8) PV generated power). The power flow direction of the stationary storage battery 7 includes discharge ((11) SB discharge power) and charge ((12) SB charge power), and can be identified by the direction of power measured by the second DC power meter 152. The power flow direction of the vehicle-mounted storage battery 8 includes discharge ((15) EV discharge power) and charge ((16) EV charge power), and can be identified by the direction of power measured by the third DC power meter 153. From the above, there are eight combinations of the power flow directions of the grid 2, the solar cell 6, the stationary storage battery 7, and the vehicle storage battery 8.

[0053] 9 is a diagram showing a schematic diagram of the power flow directions of the grid 2, solar cell 6, stationary storage battery 7, and vehicle storage battery 8 in a first pattern in the tribrid power storage system according to the embodiment. The first pattern is an example in which the power flow direction of the grid 2 is output (3), the power flow direction of the solar cell 6 is power generation (8), the power flow direction of the stationary storage battery 7 is discharge (11), and the power flow direction of the vehicle storage battery 8 is discharge (15).

[0054] 10 is a diagram showing a graph summarizing the calculation algorithm for the power value by origin in the first pattern in the tribrid power storage system according to the embodiment. In the following description, the initial values ​​of (17) the amount of power originating from PV stored in the stationary storage battery 7 and (18) the amount of power originating from the grid stored in the stationary storage battery 7 are set to 0. The initial value of (19) the amount of power originating from other sources stored in the stationary storage battery 7 is set to the remaining capacity of the stationary storage battery 7 at the time of the initial startup of the power conversion system 1.

[0055] The formulas for calculating the power values ​​according to the origin of (3) AC output power and (11) SB discharge power are as follows:

[0056] (11)_PV=(11)*(17) / [(17)+(18)+(19)]···(Formula 1) (11)_system=(11)*(18) / [(17)+(18)+(19)]···(Formula 2) (11)_Others=(11)*(19) / [(17)+(18)+(19)] (Equation 3) (3)_PV=(3)*[(8)+(11)_PV] / [(8)+(11)+(15)] (Formula 4) (3)_system=(3)*(11)_system / [(8)+(11)+(15)]···(Formula 5) (3)_Others=(3)*[(11)_Others+(15)] / [(8)+(11)+(15)] (Eq. 6)

[0057] The formulas for calculating (17) the amount of PV-derived electricity stored in the stationary storage battery 7, (18) the amount of grid-derived electricity stored in the stationary storage battery 7, and (19) the amount of other-derived electricity stored in the stationary storage battery 7 are as follows:

[0058] (17)=(17)-(11)_PV···(Formula 7) (18)=(18)-(11)_system...(Equation 8) (19) = (19) - (11) Others (Eq. 9)

[0059] The control unit 13 integrates the calculated values ​​of (11)_PV SB discharge power derived from PV, (11)_system SB discharge power derived from the system, (11)_others SB discharge power derived from others, (3)_PV AC output power derived from PV, (3)_system AC output power derived from the system, and (3)_others AC output power derived from others until the combination pattern of the power flow directions changes or 30 minutes have passed, to calculate the integrated value of the calculated power values ​​by origin. Each integrated value is cleared when the combination pattern of the power flow directions changes or 30 minutes have passed.

[0060] 11 is a diagram showing a schematic diagram of the power flow directions of the grid 2, solar cell 6, stationary storage battery 7, and vehicle storage battery 8 in the second pattern in the tribrid power storage system according to the embodiment. The second pattern is an example in which the power flow direction of the grid 2 is output (3), the power flow direction of the solar cell 6 is power generation (8), the power flow direction of the stationary storage battery 7 is discharge (11), and the power flow direction of the vehicle storage battery 8 is charge (16).

[0061] 12 is a diagram showing a graph summarizing the calculation algorithm of the power value by origin in the second pattern in the tribrid energy storage system according to the embodiment. The calculation formulas of the power value by origin of (3) AC output power, (11) SB discharge power, and (16) EV charging power are as follows.

[0062] (11)_PV=(11)*(17) / [(17)+(18)+(19)] (Equation 10) (11)_system=(11)*(18) / [(17)+(18)+(19)]···(Equation 11) (11)_Others=(11)*(19) / [(17)+(18)+(19)] (Eq. 12) (3)_PV=(3)*[(8)+(11)_PV] / [(8)+(11)] (Equation 13) (3)_system=(3)*(11)_system / [(8)+(11)]···(Equation 14) (3)_Others=(3)*(11)_Others / [(8)+(11)] (Eq. 15) (16)_PV=(16)*[(8)+(11)_PV] / [(8)+(11)]···(Formula 16) (16)_system=(16)*(11)_system / [(8)+(11)]···(Equation 17) (16)_Others=(16)*(11)_Others / [(8)+(11)] (Eq. 18)

[0063] The formulas for calculating (17) the amount of PV-derived electricity stored in the stationary storage battery 7, (18) the amount of grid-derived electricity stored in the stationary storage battery 7, and (19) the amount of other-derived electricity stored in the stationary storage battery 7 are as follows:

[0064] (17)=(17)-(11)_PV (Equation 19) (18)=(18)-(11)_system...(Equation 20) (19) = (19) - (11) other... (Eq. 21)

[0065] The control unit 13 integrates the calculated values ​​of (11)_PV SB discharge power derived from PV, (11)_system SB discharge power derived from the system, (11)_others SB discharge power derived from others, (16)_PV EV charging power derived from PV, (16)_system EV charging power derived from the system, (16)_others EV charging power derived from others, (3)_PV AC output power derived from PV, (3)_system AC output power derived from the system, and (3)_others AC output power derived from others until the combination pattern of the power flow direction changes or 30 minutes have passed, to calculate the integrated value of the calculated power value by each origin. Each integrated value is cleared when the combination pattern of the power flow direction changes or 30 minutes have passed.

[0066] 13 is a diagram showing a schematic diagram of the power flow directions of the grid 2, solar cell 6, stationary storage battery 7, and vehicle storage battery 8 in the third pattern in the tribrid power storage system according to the embodiment. The third pattern is an example in which the power flow direction of the grid 2 is output (3), the power flow direction of the solar cell 6 is power generation (8), the power flow direction of the stationary storage battery 7 is charging (12), and the power flow direction of the vehicle storage battery 8 is discharging (15).

[0067] 14 is a diagram showing a graph summarizing a calculation algorithm for the power value by origin in the third pattern in the tribrid power storage system according to the embodiment. The calculation formula for the power value by origin of (3) AC output power and (12) SB charging power is as follows.

[0068] (3)_PV=(3)*(8) / [(8)+(15)] (Equation 22) (3)_system=0...(Equation 23) (3)_Others = (3) * (15) / [(8) + (15)] (Eq. 24) (12)_PV=(12)*(8) / [(8)+(15)] (Equation 25) (12)_system=0...(Equation 26) (12)_others=(12)*(15) / [(8)+(15)] (Eq. 27)

[0069] The formulas for calculating (17) the amount of PV-derived electricity stored in the stationary storage battery 7, (18) the amount of grid-derived electricity stored in the stationary storage battery 7, and (19) the amount of other-derived electricity stored in the stationary storage battery 7 are as follows:

[0070] (17)=(17)+(12)_PV···(Formula 28) (18)=(18)+(12)_system...(Equation 29) (19) = (19) + (12)_others (Eq. 30)

[0071] The control unit 13 integrates the calculated values ​​of the SB charging power derived from (12)_PV PV, the SB charging power derived from (12)_system, the SB charging power derived from (12)_others, the AC output power derived from (3)_PV PV, the AC output power derived from (3)_system, and the AC output power derived from (3)_others until the combination pattern of the power flow directions changes or 30 minutes have passed, to calculate the integrated value of the calculated power values ​​by origin. Each integrated value is cleared when the combination pattern of the power flow directions changes or 30 minutes have passed.

[0072] 15 is a diagram showing a schematic diagram of the power flow directions of the grid 2, solar cell 6, stationary storage battery 7, and vehicle storage battery 8 in a fourth pattern in the tribrid power storage system according to the embodiment. The fourth pattern is an example in which the power flow direction of the grid 2 is output (3), the power flow direction of the solar cell 6 is power generation (8), the power flow direction of the stationary storage battery 7 is charging (12), and the power flow direction of the vehicle storage battery 8 is charging (16).

[0073] 16 is a diagram showing a graph summarizing the calculation algorithm of the power value by origin in the fourth pattern in the tribrid power storage system according to the embodiment. The calculation formulas of the power value by origin of (3) AC output power, (12) SB charging power, and (16) EV charging power are as follows.

[0074] (3)_PV=(3)...(Formula 31) (3)_System=0...(Formula 32) (3)_Others = 0 (Eq. 33) (12)_PV=(12)...(Formula 34) (12)_system=0...(Equation 35) (12)_Others = 0 (Eq. 36) (16)_PV=(16)...(Formula 37) (16)_system=0...(Equation 38) (16)_Others = 0 (Eq. 39)

[0075] The formulas for calculating (17) the amount of PV-derived electricity stored in the stationary storage battery 7, (18) the amount of grid-derived electricity stored in the stationary storage battery 7, and (19) the amount of other-derived electricity stored in the stationary storage battery 7 are as follows:

[0076] (17)=(17)+(12)_PV···(Formula 40) (18)=(18)+(12)_system...(Equation 41) (19) = (19) + (12)_others (Eq. 42)

[0077] The control unit 13 integrates the calculated values ​​of the SB charging power derived from (12)_PV PV, the SB charging power derived from (12)_system, the SB charging power derived from (12)_others, the EV charging power derived from (16)_PV PV, the EV charging power derived from (16)_system, the EV charging power derived from (16)_others, the AC output power derived from (3)_PV PV, the AC output power derived from (3)_system, and the AC output power derived from (3)_others until the combination pattern of the power flow directions changes or 30 minutes have passed, to calculate the integrated value of the calculated power values ​​by origin. Each integrated value is cleared when the combination pattern of the power flow directions changes or 30 minutes have passed.

[0078] 17 is a diagram showing a schematic diagram of the power flow directions of the grid 2, solar cell 6, stationary storage battery 7, and vehicle storage battery 8 in the fifth pattern in the tribrid power storage system according to the embodiment. The fifth pattern is an example in which the power flow direction of the grid 2 is input (4), the power flow direction of the solar cell 6 is power generation (8), the power flow direction of the stationary storage battery 7 is discharge (11), and the power flow direction of the vehicle storage battery 8 is discharge (15).

[0079] 18 is a diagram showing a graph summarizing a calculation algorithm for the power value by origin in the fifth pattern in the tribrid power storage system according to the embodiment. (11) The calculation formula for the power value by origin of the SB discharge power is as follows.

[0080] (11)_PV=(11)*(17) / [(17)+(18)+(19)]···(Formula 43) (11)_System=(11)*(18) / [(17)+(18)+(19)]···(Formula 44) (11)_others=(11)*(19) / [(17)+(18)+(19)] (Eq. 45)

[0081] The formulas for calculating (17) the amount of PV-derived electricity stored in the stationary storage battery 7, (18) the amount of grid-derived electricity stored in the stationary storage battery 7, and (19) the amount of other-derived electricity stored in the stationary storage battery 7 are as follows:

[0082] (17)=(17)-(11)_PV...(Formula 46) (18)=(18)-(11)_system...(Equation 47) (19) = (19) - (11) other... (Eq. 48)

[0083] The control unit 13 integrates the calculated values ​​of (11)_PV SB discharge power originating from PV, (11)_Grid SB discharge power originating from grid, and (11)_Other SB discharge power originating from others until the combination pattern of the power flow directions changes or 30 minutes have passed, to calculate the integrated value of the calculated power values ​​by origin. Each integrated value is cleared when the combination pattern of the power flow directions changes or 30 minutes have passed.

[0084] 19 is a diagram showing a schematic diagram of the power flow directions of the grid 2, solar cell 6, stationary storage battery 7, and vehicle storage battery 8 in the sixth pattern in the tribrid power storage system according to the embodiment. The sixth pattern is an example in which the power flow direction of the grid 2 is input (4), the power flow direction of the solar cell 6 is power generation (8), the power flow direction of the stationary storage battery 7 is discharge (11), and the power flow direction of the vehicle storage battery 8 is charge (16).

[0085] 20 is a diagram showing a graph summarizing the calculation algorithm of the power value by origin in the sixth pattern in the tribrid energy storage system according to the embodiment. The calculation formula of the power value by origin of (11) SB discharge power and (16) EV charge power is as follows.

[0086] (11)_PV=(11)*(17) / [(17)+(18)+(19)]···(Formula 49) (11)_System=(11)*(18) / [(17)+(18)+(19)]···(Formula 50) (11)_others=(11)*(19) / [(17)+(18)+(19)] (Eq. 51) (16)_PV=(16)*[(8)+(11)_PV] / [(4)+(8)+(11)]···(Formula 52) (16)_system=(16)*[(4)+(11)_system] / [(4)+(8)+(11)]···(Formula 53) (16)_Others=(16)*(11)_System / [(4)+(8)+(11)] (Eq. 54)

[0087] The formulas for calculating (17) the amount of PV-derived electricity stored in the stationary storage battery 7, (18) the amount of grid-derived electricity stored in the stationary storage battery 7, and (19) the amount of other-derived electricity stored in the stationary storage battery 7 are as follows:

[0088] (17)=(17)-(11)_PV...(Formula 55) (18)=(18)-(11)_system...(Equation 56) (19) = (19) - (11) other... (Eq. 57)

[0089] The control unit 13 integrates the calculated values ​​of the SB discharge power derived from (11)_PV PV, the SB discharge power derived from (11)_system, the SB discharge power derived from (11)_others, the EV charging power derived from (16)_PV PV, the EV charging power derived from (16)_system, and the EV charging power derived from (16)_others until the combination pattern of the power flow direction changes or 30 minutes have passed, to calculate the integrated value of the calculated power value by each origin. Each integrated value is cleared when the combination pattern of the power flow direction changes or 30 minutes have passed.

[0090] 21 is a diagram showing a schematic diagram of the power flow directions of the grid 2, solar cell 6, stationary storage battery 7, and vehicle storage battery 8 in the seventh pattern in the tribrid power storage system according to the embodiment. The seventh pattern is an example in which the power flow direction of the grid 2 is input (4), the power flow direction of the solar cell 6 is power generation (8), the power flow direction of the stationary storage battery 7 is charging (12), and the power flow direction of the vehicle storage battery 8 is discharging (15).

[0091] 22 is a diagram showing a graph summarizing a calculation algorithm for the power value by origin in the seventh pattern in the tribrid power storage system according to the embodiment. (12) The calculation formula for the power value by origin of the SB charging power is as follows.

[0092] (12)_PV=(12)*(8) / [(4)+(8)+(15)]...(Formula 58) (12)_system=(12)*(4) / [(4)+(8)+(15)]...(Formula 59) (12)_Others=(12)*(15) / [(4)+(8)+(15)] (Eq. 60)

[0093] The formulas for calculating (17) the amount of PV-derived electricity stored in the stationary storage battery 7, (18) the amount of grid-derived electricity stored in the stationary storage battery 7, and (19) the amount of other-derived electricity stored in the stationary storage battery 7 are as follows:

[0094] (17)=(17)+(12)_PV...(Formula 61) (18)=(18)+(12)_system...(Equation 62) (19) = (19) + (12)_others (Eq. 63)

[0095] The control unit 13 integrates the calculated values ​​of the SB charging power derived from (12)_PV PV, the SB charging power derived from (12)_Grid, and the SB charging power derived from (12)_Other until the combination pattern of the power flow directions changes or 30 minutes have passed, to calculate the integrated value of the calculated power values ​​by origin. Each integrated value is cleared when the combination pattern of the power flow directions changes or 30 minutes have passed.

[0096] 23 is a diagram showing a schematic diagram of the power flow directions of the grid 2, solar cell 6, stationary storage battery 7, and vehicle storage battery 8 in the eighth pattern in the tribrid power storage system according to the embodiment. The eighth pattern is an example in which the power flow direction of the grid 2 is input (4), the power flow direction of the solar cell 6 is power generation (8), the power flow direction of the stationary storage battery 7 is charging (12), and the power flow direction of the vehicle storage battery 8 is charging (16).

[0097] 24 is a diagram showing a graph summarizing the calculation algorithm of the power value by origin in the eighth pattern in the tribrid power storage system according to the embodiment. The calculation formula of the power value by origin of (12) SB charging power and (16) EV charging power is as follows.

[0098] (12)_PV=(12)*(8) / [(4)+(8)] (Formula 64) (12)_System=(12)*(4) / [(4)+(8)]···(Formula 65) (12)_Others = 0 (Eq. 66) (16)_PV=(16)*(8) / [(4)+(8)] (Formula 67) (16)_System=(16)*(4) / [(4)+(8)]···(Formula 68) (16)_Others = 0 (Eq. 69)

[0099] The formulas for calculating (17) the amount of PV-derived electricity stored in the stationary storage battery 7, (18) the amount of grid-derived electricity stored in the stationary storage battery 7, and (19) the amount of other-derived electricity stored in the stationary storage battery 7 are as follows:

[0100] (17)=(17)+(12)_PV...(Formula 70) (18)=(18)+(12)_system...(Formula 71) (19) = (19) + (12)_others (Eq. 72)

[0101] The control unit 13 integrates the calculated values ​​of the SB charging power derived from (12)_PV PV, the SB charging power derived from (12)_system, the SB charging power derived from (12)_others, the EV charging power derived from (16)_PV PV, the EV charging power derived from (16)_system, and the EV charging power derived from (16)_others until the combination pattern of the power flow directions changes or 30 minutes have passed, to calculate the integrated value of the calculated power values ​​by origin. Each integrated value is cleared when the combination pattern of the power flow directions changes or 30 minutes have passed.

[0102] As described above, the control unit 13 specifies a combination pattern of power flow directions based on the directions of power measured by the AC power meter 14, the second DC power meter 152, and the third DC power meter 153. In the case of the first pattern, the second pattern, the fifth pattern, or the sixth pattern, the control unit 13 calculates (11)_PV SB discharge power derived from PV, (11)_system SB discharge power derived from the system, and (11)_other SB discharge power derived from others.

[0103] The control unit 13 updates the amount of power derived from PV (17) stored in the stationary storage battery 7 by subtracting the SB discharge power derived from PV (11)_PV from the amount of power derived from PV stored in the stationary storage battery 7. The control unit 13 updates the amount of power derived from the grid (18) stored in the stationary storage battery 7 by subtracting the SB discharge power derived from the grid (11)_Grid from the amount of power derived from the grid stored in the stationary storage battery 7. The control unit 13 updates the amount of power derived from others (19) stored in the stationary storage battery 7 by subtracting the SB discharge power derived from others (11)_Other from the amount of power derived from others stored in the stationary storage battery 7.

[0104] In the case of the third, fourth, seventh, or eighth pattern, the control unit 13 calculates the SB charging power derived from (12)_PV, the SB charging power derived from (12)_system, and the SB charging power derived from (12)_others.

[0105] The control unit 13 updates the amount of power derived from PV (17) stored in the stationary storage battery 7 by adding the SB charging power derived from PV (12)_PV to the amount of power derived from PV stored in the stationary storage battery 7. The control unit 13 updates the amount of power derived from the grid (18) stored in the stationary storage battery 7 by adding the SB charging power derived from the grid (12)_Grid to the amount of power derived from the grid stored in the stationary storage battery 7. The control unit 13 updates the amount of power derived from others (19) stored in the stationary storage battery 7 by adding the SB charging power derived from others (12)_Other to the amount of power derived from others stored in the stationary storage battery 7.

[0106] The control unit 13 calculates the ratio of the power originating from the solar cell 6 in the power measured by the second DC power meter 152 based on the amount of power originating from the solar cell 6, the amount of power originating from the grid 2, the amount of power originating from other sources, and the power measured by the second DC power meter 152, which are stored in the stationary storage battery 7. More specifically, the control unit 13 calculates the ratio of the remaining capacity originating from the solar cell 6 in the total remaining capacity of the stationary storage battery 7, and multiplies this by the power measured by the second DC power meter 152 to calculate the ratio of the power originating from the solar cell 6 in the power measured by the second DC power meter 152.

[0107] In the first pattern, the control unit 13 calculates the AC output power derived from the solar cell 6 output from the power conversion system 1 to the distribution board 3 based on the ratio of the power derived from the solar cell 6 to the power measured by the AC power meter 14, the first DC power meter 151, the second DC power meter 152, and the third DC power meter 153, respectively, and the power measured by the second DC power meter 152, as shown in the above (Equation 4).

[0108] In the second pattern, the control unit 13 calculates the AC output power derived from the solar cell 6 based on the power measured by the AC power meter 14, the first DC power meter 151, and the second DC power meter 152, respectively, and the ratio of the power measured by the second DC power meter 152 that is derived from the solar cell 6, as shown in the above (Equation 13).

[0109] In the third pattern, the control unit 13 calculates the AC output power from the solar cell 6 based on the power measured by the AC power meter 14, the first DC power meter 151, and the third DC power meter 153, as shown in the above (Equation 22).

[0110] In the fourth pattern, the control unit 13 calculates the AC output power derived from the solar cell 6 based on the power measured by the AC power meter 14, as shown in the above (Equation 31).

[0111] The PPA operator can use the integrated value of the AC output power derived from the solar cell 6 as basic data when billing for electricity consumed by the home load 4. The PPA operator can also use the integrated value of the EV charging power derived from the solar cell 6 as basic data when billing for electricity consumed by the electric vehicle. The integrated value of the EV charging power derived from the grid 2 can also be used as the amount of power charged from the grid 2 to the electric vehicle.

[0112] When the tolerance of the power at the measurement points measured by the first DC power meter 151 to the third DC power meter 153 falls within the n3 class (3%), the allocation of the power charged to the stationary storage battery 7 always falls within the range of -3% to +3%.

[0113] The term (17) / [(17)+(18)+(19)] in the above (Equation 1), (Equation 10), (Equation 43), and (Equation 59) is the ratio of power measured with the same DC power meter. For example, if the tolerance of the DC power meter is 3%, then a*1.03 / (a*1.03+b*1.03+c*1.03)=a*1.03 / (a+b+c)*1.03=a / (a+b+c), and the errors of the DC power meter cancel each other out.

[0114] Fig. 25 is a diagram showing the configuration of a hybrid power storage system according to an embodiment equipped with a function for measuring the amount of power by source. In the hybrid power storage system, the in-vehicle storage battery 8 is not connected to the power conversion system 1, and the third DC / DC converter 11c and the third DC power meter 153 are omitted. In the hybrid power storage system, (15) EV discharge power and (16) EV charge power are omitted in the calculation algorithm for the power value by source described in Figs. 8 to 24. (19) The amount of power from other sources stored in the stationary storage battery 7 is also omitted, and the amount of power stored in the stationary storage battery 7 is the sum of the amount of power from PV and the amount of power from the grid.

[0115] As described above, according to this embodiment, in a hybrid or tribrid energy storage system, a specified meter of n2 class or n3 class is installed, and the power value by origin at each measurement point and the remaining capacity by origin of the stationary storage battery 7 are calculated as shown in the above (Equation 1) to (Equation 72). This makes it possible to estimate the ratio of the origin component at each measurement point with high accuracy. Therefore, it is possible to measure the amount of power by origin that satisfies the tolerance conditions in the guidelines related to the specified metering system. When the tolerance of the power at the measurement points measured by the first DC power meter 151 to the third DC power meter 153 falls within the n3 class, in the hybrid or tribrid energy storage system according to the embodiment, it falls almost within range A for a transaction scale of 10 kW or less in the table of tolerance classes shown in FIG. 2.

[0116] Although conversion losses occur before and after the first DC / DC converter 11a, before and after the second DC / DC converter 11b, before and after the third DC / DC converter 11c, and before and after the inverter 12, the ratio of the power-derived component does not change. Therefore, even if the fourth DC power meter 154 to the seventh DC power meter 157 are omitted as shown in the comparative example of Fig. 4, the ratio of the power derived from the remaining capacity stored in the stationary storage battery 7 and the ratio of the power derived from the AC output power measured by the AC power meter 14 can be estimated with high accuracy. Therefore, by multiplying the AC output power measured by the AC power meter 14 by the ratio of the power derived from the solar cell 6, the AC output power derived from the solar cell 6 can be calculated with high accuracy.

[0117] The accuracy of the AC output power derived from the solar cell 6 is approximately equivalent to the accuracy of the AC output power derived from the solar cell 6 calculated after removing the effect of conversion loss by installing specified meters respectively before and after the first DC / DC converter 11a, before and after the second DC / DC converter 11b, before and after the third DC / DC converter 11c, and before and after the inverter 12, as shown in the comparative example. In this embodiment, the fourth DC power meter 154 to the seventh DC power meter 157 can be omitted, so that the cost can be significantly reduced compared to the comparative example.

[0118] By calculating the AC output power from solar cells 6 using the calculation algorithm for power values ​​by source in the embodiment, the PPA operator can charge the customer for the electricity consumed by the solar power generation in a hybrid or tribrid energy storage system on a pay-as-you-go basis.

[0119] By the way, Japan has the J-Credit Scheme, in which the government certifies the amount of greenhouse gas emission reduction or absorption as a credit. In the J-Credit Scheme, the amount of charge and discharge loss in a storage battery is defined as shown below (Equation 73). Charging and discharging loss (kWh / year) = home power consumption (kWh / year) × battery usage rate (%) × (1-charging efficiency (%) / 100(%) × discharging efficiency (%) / 100(%)) (Equation 73)

[0120] It is stipulated that the amount of electricity (kWh / year) that passes through the storage battery is multiplied by 60% from the default value if the storage battery capacity is 4kWh or less, and by 70% if it is more than 4kWh. In addition, the charging and discharging efficiency (%) is to be determined from the catalog or specifications of the storage battery. If it cannot be determined, it is stipulated that the default value (90% for both charging and discharging efficiency) is to be used.

[0121] Because the conditions are set strict so that J Credit is not put at a disadvantage, only the amount of electricity less than the actual amount of electricity used is certified as environmental value for the amount of self-consumption electricity from solar power generation via a storage battery. By adopting the amount of self-consumption electricity from solar power generation calculated by the calculation algorithm for the power value by source according to the present embodiment, it is possible to certify environmental value that is in line with the actual amount of electricity used.

[0122] The present disclosure has been described above based on the embodiments. The embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component and each processing step, and that such modifications are also within the scope of the present disclosure.

[0123] In the above embodiment, an example has been described in which the solar cell 6 is used as a power generation device that converts renewable energy into electrical energy. In this regard, a wind power generator or a micro-hydroelectric generator can be used instead of the solar cell 6. In this case, a rectifier is connected between the wind power generator or the micro-hydroelectric generator and the first DC / DC converter 11a.

[0124] The embodiment may be specified by the following items.

[0125] [Item 1] a first DC / DC converter (11a) connected to a power generation device (6) that converts renewable energy into electrical energy; a second DC / DC converter (11b) connected to the stationary power storage unit (7); an inverter (12) having a DC terminal connected to a junction (N1) of the first DC / DC converter (11a) and the second DC / DC converter (11b) and having an AC terminal connected to a distribution board (3) connected to a system (2) and a load (4); an AC power meter (14) installed between the inverter (12) and the distribution board (3); a first DC power meter (151) installed between the first DC / DC converter (11a) and the power generation device (6); a second DC power meter (152) installed between the second DC / DC converter (11b) and the stationary power storage unit (7); and a control unit (13) that measures the amount of power originating from the power generation device (6) and output to the distribution board (3) based on the power measured by the AC power meter (14) and the first DC power meter (151) to the second DC power meter (152). Power conversion system (1). According to this, in the hybrid configuration, the amount of electric power originating from the power generation device (6) and output to the distribution board (3) can be measured with high accuracy. [Item 2] The control unit (13) calculating the power derived from the power generation device (6) and the power derived from the grid (2) that are charged to the stationary power storage unit (7) based on the values ​​of the power measured by the AC power meter (14) and the first DC power meter (151) and the second DC power meter (152), respectively, and the directions of the power measured by the AC power meter (14) and the second DC power meter (152), adding the electric power derived from the power generation device (6) to be charged into the stationary electric storage unit (7) to the amount of electric power derived from the power generation device (6) stored in the stationary electric storage unit (7); adding the power derived from the grid (2) to be charged into the stationary power storage unit (7) to the amount of power derived from the grid (2) stored in the stationary power storage unit (7); Calculating the amount of power derived from the power generation device (6) and the amount of power derived from the grid (2) that are discharged from the stationary storage unit (7) based on the amount of power derived from the power generation device (6) and the amount of power derived from the grid (2) that are stored in the stationary storage unit (7), the values ​​of power measured by the AC power meter (14) and the first DC power meter (151) - the second DC power meter (152), respectively, and the directions of power measured by the AC power meter (14) and the second DC power meter (152), respectively; subtracting the electric power originating from the power generation device (6) discharged from the stationary electric storage unit (7) from the amount of electric power originating from the power generation device (6) stored in the stationary electric storage unit (7); The electric power derived from the grid (2) discharged from the stationary electric storage unit (7) is subtracted from the amount of electric power derived from the grid (2) stored in the stationary electric storage unit (7). Item 1. A power conversion system (1) as described in item 1. This makes it possible to estimate with high accuracy the amount of electric power derived from the power generation device (6) and the amount of electric power derived from the grid (2) stored in the stationary electric storage unit (7). [Item 3] The control unit (13) calculating a ratio of the power originating from the power generation device (6) to the power measured by the second DC power meter (152) based on the amount of power originating from the power generation device (6) stored in the stationary power storage unit (7), the amount of power originating from the grid (2) stored in the stationary power storage unit (7), and the power measured by the second DC power meter (152); When the stationary power storage unit (7) is discharging, the power originating from the power generation device (6) and output to the distribution board (3) is calculated based on the power measured by the AC power meter (14), the power measured by the first DC power meter (151), the power measured by the second DC power meter (152), and the ratio of the power originating from the power generation device (6) to the power measured by the second DC power meter (152); When the stationary storage unit (7) is being charged, the power from the power generation device (6) to be output to the distribution board (3) is calculated based on the power measured by the AC power meter (14). 3. The power conversion system (1) according to item 2. According to this, in the hybrid configuration, the electric power derived from the power generation device (6) and output to the distribution board (3) can be calculated with high accuracy. [Item 4] The AC power meter (14) and the first DC power meter (151) - the second DC power meter (152) are specified measuring instruments. 4. A power conversion system (1) according to any one of items 1 to 3. According to this, in a hybrid configuration, it is possible to meet the conditions required by the guidelines related to the specific measurement system without installing a smart meter between the power conversion system (1) and the distribution board (3). [Item 5] a third DC / DC converter (11c) connected between the vehicle-mounted power storage unit (8) and the junction (N1); a third DC power meter (153) disposed between the third DC / DC converter (11c) and the vehicle-mounted power storage unit (8), The control unit (13) measures the amount of power originating from the power generation device (6) and output to the distribution board (3) based on the power measured by the AC power meter (14) and the first DC power meter (151) to the third DC power meter (153). Item 1. A power conversion system (1) as described in item 1. According to this, in the tribrid configuration, the amount of electric power originating from the power generation device (6) and output to the distribution board (3) can be measured with high accuracy. [Item 6] The control unit (13) Calculating the amount of power derived from the power generation device (6), the amount of power derived from the grid (2), and the amount of power derived from other sources that are charged to the stationary power storage unit (7), based on the values ​​of power measured by the AC power meter (14) and the first DC power meter (151) - the third DC power meter (153), respectively, and the directions of power measured by the AC power meter (14) and the second DC power meter (152) - the third DC power meter (153), respectively; adding the electric power derived from the power generation device (6) to be charged into the stationary electric storage unit (7) to the amount of electric power derived from the power generation device (6) stored in the stationary electric storage unit (7); adding the power derived from the grid (2) to be charged into the stationary power storage unit (7) to the amount of power derived from the grid (2) stored in the stationary power storage unit (7); adding the electric power from other sources charged to the stationary electric storage unit (7) to the amount of electric power from other sources stored in the stationary electric storage unit (7); Calculating the amount of power derived from the power generation device (6), the amount of power derived from the grid (2), and the amount of power derived from other sources, which are stored in the stationary storage unit (7), the values ​​of power measured by the AC power meter (14) and the first DC power meter (151) to the third DC power meter (153), and the directions of power measured by the AC power meter (14) and the second DC power meter (152) to the third DC power meter (153), which are stored in the stationary storage unit (7), and calculating the amount of power derived from the power generation device (6), the amount of power derived from the grid (2), and the amount of power derived from other sources, which are discharged from the stationary storage unit (7); subtracting the electric power originating from the power generation device (6) discharged from the stationary electric storage unit (7) from the amount of electric power originating from the power generation device (6) stored in the stationary electric storage unit (7); subtracting the power derived from the grid (2) discharged from the stationary power storage unit (7) from the amount of power derived from the grid (2) stored in the stationary power storage unit (7); The amount of electric power from other sources discharged from the stationary power storage unit (7) is subtracted from the amount of electric power from other sources stored in the stationary power storage unit (7). 6. The power conversion system (1) according to item 5. This makes it possible to estimate with high accuracy the amount of electric power stored in the stationary power storage unit (7) derived from the power generation device (6), the amount of electric power derived from the grid (2), and the amount of electric power derived from other sources. [Item 7] The control unit (13) calculating a ratio of the power originating from the power generation device (6) to the power measured by the second DC power meter (152), based on the amount of power originating from the power generation device (6) stored in the stationary power storage unit (7), the amount of power originating from the grid (2) stored in the stationary power storage unit (7), the amount of power originating from the other sources stored in the stationary power storage unit (7), and the power measured by the second DC power meter (152); When the stationary power storage unit (7) is discharging and the vehicle-mounted power storage unit (8) is discharging, the power derived from the power generation device (6) and output to the distribution board (3) is calculated based on a ratio of the power derived from the power generation device (6) among the powers measured by the AC power meter (14), the first DC power meter (151), the third DC power meter (153), and the power measured by the second DC power meter (152); When the stationary power storage unit (7) is discharging and the vehicle-mounted power storage unit (8) is charging, the power derived from the power generation device (6) to be output to the distribution board (3) is calculated based on the power measured by the AC power meter (14), the power measured by the first DC power meter (151) and the power measured by the second DC power meter (152), respectively, and the ratio of the power derived from the power generation device (6) to the power measured by the second DC power meter (152); When the stationary storage unit (7) is charging and the vehicle-mounted storage unit (8) is discharging, the power derived from the power generation device (6) and output to the distribution board (3) is calculated based on the power measured by the AC power meter (14), the first DC power meter (151), and the third DC power meter (153), respectively; When the stationary storage unit (7) is charging and the vehicle-mounted storage unit (8) is charging, the power derived from the power generation device (6) and output to the distribution board (3) is calculated based on the power measured by the AC power meter (14). 7. The power conversion system (1) according to item 6. According to this, in the tribrid configuration, the electric power originating from the power generation device (6) and output to the distribution board (3) can be calculated with high accuracy. [Item 8] The AC power meter (14) and the first DC power meter (151) to the third DC power meter (153) are specified measuring instruments. 8. The power conversion system (1) according to any one of items 5 to 7. According to this, in a tribrid configuration, it is possible to meet the conditions required by the guidelines related to the specific measurement system without installing a smart meter between the power conversion system (1) and the distribution board (3). [Explanation of symbols]

[0126] 1 power conversion system, 2 system, 3 distribution board, 4 domestic load, 5,5a smart meter, 6 solar cell, 7 stationary storage battery, 8 vehicle storage battery, 9 network, 10 PPA operator server, 11a first DC / DC converter, 11b second DC / DC converter, 11c third DC / DC converter, 12 inverter, 13 control unit, 14 AC power meter, 151-157 DC power meters, Bd DC bus.

Claims

1. A first DC / DC converter connected to a power generation device that converts renewable energy into electrical energy; a second DC / DC converter connected to the stationary power storage unit; an inverter having a DC terminal connected to a junction of the first DC / DC converter and the second DC / DC converter and an AC terminal connected to a distribution board connected to a system and a load; an AC power meter installed between the inverter and the distribution board; a first DC power meter installed between the first DC / DC converter and the power generation device; a second DC power meter installed between the second DC / DC converter and the stationary power storage unit; and a control unit that measures the amount of power originating from the power generation device output to the distribution board based on the power measured by the AC power meter and the first DC power meter and the second DC power meter, Power conversion systems.

2. The control unit is calculating the power derived from the power generation device and the power derived from the grid that are charged to the stationary power storage unit based on values ​​of power measured by the AC power meter and the first DC power meter-the second DC power meter, and the directions of power measured by the AC power meter and the second DC power meter, adding the electric power derived from the power generation device to be charged into the stationary power storage unit to the amount of electric power derived from the power generation device and stored in the stationary power storage unit; adding the power derived from the grid to be charged into the stationary power storage unit to an amount of power derived from the grid and stored in the stationary power storage unit; calculating the power derived from the power generation device and the power derived from the grid that are discharged from the stationary power storage unit based on the amount of power derived from the power generation device and the amount of power derived from the grid that are stored in the stationary power storage unit, the values ​​of power measured by the AC power meter and the first DC power meter-the second DC power meter, respectively, and the directions of power measured by the AC power meter and the second DC power meter, respectively; subtracting the power originating from the power generation device discharged from the stationary power storage unit from the amount of power originating from the power generation device stored in the stationary power storage unit; subtracting the power derived from the grid discharged from the stationary power storage unit from the amount of power derived from the grid stored in the stationary power storage unit; The power conversion system of claim 1 .

3. The control unit is calculating a ratio of the power originating from the power generation device to the power measured by the second DC power meter based on the amount of power originating from the power generation device and stored in the stationary power storage unit, the amount of power originating from the grid and stored in the stationary power storage unit, and the power measured by the second DC power meter; When the stationary power storage unit is discharging, the power originating from the power generation device and output to the distribution board is calculated based on the powers measured by the AC power meter, the powers measured by the first DC power meter and the second DC power meter, and a ratio of the power originating from the power generation device to the power measured by the second DC power meter; When the stationary power storage unit is being charged, the power originating from the power generation device and output to the distribution board is calculated based on the power measured by the AC power meter. The power conversion system of claim 2 .

4. The AC power meter and the first DC power meter - the second DC power meter are specified measuring instruments. The power conversion system according to claim 1 .

5. a third DC / DC converter connected between the vehicle-mounted power storage unit and the junction point; a third DC power meter disposed between the third DC / DC converter and the vehicle-mounted power storage unit, The control unit measures the amount of power originating from the power generation device output to the distribution board based on the power measured by the AC power meter and the first DC power meter to the third DC power meter, The power conversion system of claim 1 .

6. The control unit is calculating the power derived from the power generation device, the power derived from the grid, and the power derived from other sources, which are charged to the stationary power storage unit, based on values ​​of power measured by the AC power meter and the first DC power meter-the third DC power meter, respectively, and the directions of power measured by the AC power meter and the second DC power meter-the third DC power meter, respectively; adding the electric power derived from the power generation device to be charged into the stationary power storage unit to the amount of electric power derived from the power generation device and stored in the stationary power storage unit; adding the power derived from the grid to be charged into the stationary power storage unit to an amount of power derived from the grid and stored in the stationary power storage unit; adding the electric power from other sources charged to the stationary power storage unit to an amount of electric power from other sources stored in the stationary power storage unit; calculating the power derived from the power generation device, the power derived from the grid, and the power derived from the other sources that are discharged from the stationary power storage unit based on the amount of power derived from the power generation device, the amount of power derived from the grid, and the amount of power derived from the other sources that are stored in the stationary power storage unit, the values ​​of power measured by the AC power meter and the first DC power meter-the third DC power meter, and the directions of power measured by the AC power meter and the second DC power meter-the third DC power meter, subtracting the power originating from the power generation device discharged from the stationary power storage unit from the amount of power originating from the power generation device stored in the stationary power storage unit; subtracting the power derived from the grid discharged from the stationary power storage unit from the amount of power derived from the grid stored in the stationary power storage unit; subtracting the amount of power from other sources discharged from the stationary power storage unit from the amount of power from other sources stored in the stationary power storage unit; The power conversion system of claim 5 .

7. The control unit is calculating a ratio of the power originating from the power generation device to the power measured by the second DC power meter based on the amount of power originating from the power generation device and stored in the fixed power storage unit, the amount of power originating from the grid and stored in the fixed power storage unit, the amount of power originating from other sources and stored in the fixed power storage unit, and the power measured by the second DC power meter; when the stationary power storage unit is discharging and the vehicle-mounted power storage unit is discharging, calculates the power derived from the power generation device that is output to the distribution board based on a ratio of the power derived from the power generation device among the powers measured by the AC power meter, the first DC power meter and the third DC power meter, and the power measured by the second DC power meter; when the stationary power storage unit is discharging and the vehicle-mounted power storage unit is charging, calculates the power originating from the power generation device and output to the distribution board based on the powers measured by the AC power meter and the first DC power meter-the second DC power meter, and the ratio of the power originating from the power generation device to the power measured by the second DC power meter; when the stationary power storage unit is charging and the vehicle-mounted power storage unit is discharging, calculates the power derived from the power generation device that is output to the distribution board based on the power measured by the AC power meter, the first DC power meter, and the third DC power meter, When the stationary power storage unit is charging and the vehicle-mounted power storage unit is charging, the power originating from the power generation device and output to the distribution board is calculated based on the power measured by the AC power meter. The power conversion system of claim 6 .

8. The AC power meter and the first DC power meter to the third DC power meter are specified measuring instruments. The power conversion system according to any one of claims 5 to 7.

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