JP7103811B2 - Power supply system - Google Patents

Description

The present invention relates to a technique of a power supply system including a power storage device capable of charging and discharging power from a power generation unit.

Conventionally, a technique of a power supply system including a power storage device capable of charging and discharging power from a power generation unit has been known. For example, as described in Patent Document 1.

Patent Document 1 describes a power supply system including a photovoltaic power generation unit and a power storage device capable of charging and discharging the power from the photovoltaic power generation unit. The power supply system is capable of reverse power flow (selling) of surplus power from the photovoltaic power generation unit to a commercial power source, and is configured to charge a power storage device with midnight power having a low unit price. There is. As a result, the utility cost can be reduced.

However, the unit selling price of photovoltaic power generation has been declining in recent years, and may be lower than the daytime power price, for example. Therefore, in the power supply system described in Patent Document 1, if there is such a fluctuation in the power unit price, it may not be possible to minimize the utility cost.

Japanese Unexamined Patent Publication No. 2014-45635

The present invention has been made in view of the above circumstances, and the problem to be solved is to provide a power supply system capable of reducing utility costs in response to fluctuations in the unit price of power.

The problem to be solved by the present invention is as described above, and next, the means for solving this problem will be described.

That is, in claim 1, a power generation unit capable of generating power by using natural energy and selling the generated power to a commercial power source, a commercial power source from the commercial power source, and a power generation unit from the power generation unit. A power storage device capable of charging and discharging generated power and a control unit for controlling charging and discharging of the power storage device are provided, and the control unit purchases the commercial power when the power storage device is charged with the commercial power. Charging, which is the average unit price of charged power, based on the unit price of electricity at the time of charging, which is the unit price of electricity, and the unit price of electricity at the time of charging, which is the unit price of selling the generated power when the power storage device is charged. It is possible to calculate a unit price, control charging / discharging of the power storage device based on the calculated charging unit price, and execute a planning process for determining a charging timing which is a time zone in which the power storage device can be charged. In the first time zone in which the surplus of the generated power is generated with respect to the power demand, the second time zone in which the purchase unit price of the commercial power is the minimum, or the power purchase unit price of the commercial power is the generated power. The third time zone, which is less than the unit price of electricity sold, is predicted, and the predicted first time zone, the second time zone, and the third time zone are set as the charging timing, and the charging timing is the same. It is possible to determine the target charge amount, which is the charge amount to be charged to the power storage device, from the first charge timing, which is one of the charge timings, to the second charge timing, which is the next charge timing after the first charge timing. The power demand and the power generation amount of the power generation unit are predicted, the target charge amount at the first charge timing is determined based on the predicted power demand and the power generation amount, and the charge time during the first time zone. The unit price is set in ascending order of priority with respect to the unit price of electricity sold, the unit price of electricity purchased during charging in the second time zone, and the unit price of electricity purchased during charging in the third time zone. The target charge amount at the highest charge timing is corrected to the maximum capacity of the power storage device .

In the second aspect, when the control unit does not reach the maximum capacity even if it is charged with the maximum capacity of the power storage device at the charging timing having the highest priority in the planning process, the priority is changed. The shortage is added to the target charge amount at the second highest charge timing.

In claim 3 , when the charge unit price is lower than the current power purchase unit price of the commercial power, the control unit discharges the power storage device according to the power demand.

In claim 4 , the fuel cell capable of generating electricity by using fuel is provided, and the control unit determines that the unit price of power generation of the fuel cell is lower than the unit price of charging and the current unit price of purchasing commercial power. The fuel cell is to generate electricity.

In claim 5 , the control unit discharges the power storage device when the charge unit price is lower than the power generation unit price of the fuel cell and the current power purchase unit price of the commercial power.

In claim 6 , the control unit has the charge unit price lower than the power generation unit price of the fuel cell and the current power generation unit price of the commercial power, and the power generation unit price of the fuel cell is the current commercial power generation unit price. When the unit price of electricity is lower than the unit purchase price of electricity, the electricity storage device is discharged so that the discharge amount of the electricity storage device at each time is averaged, and the averaged discharge amount is all or one of the predicted power demands. If the part cannot be covered, the fuel cell is generated to generate electricity.

As the effect of the present invention, the following effects are exhibited.

In claim 1, the utility cost can be reduced according to the fluctuation of the electric power unit price. Further, in claim 1, the power storage device can be charged at the timing when surplus electric power is generated or at the timing when the unit price of the electric power to be charged is low. Further, in claim 1, the electric power demand until the next charging timing (second charging timing) can be covered by the electric power discharged from the power storage device. Further, in claim 1, since a large amount of electric power having a low electric power unit price can be charged, the utility cost can be reduced.

In claim 2 , even if the power charged at the charging timing with the lowest power unit price cannot meet the power demand, the power charged at the charging timing with the second lowest power unit price can cover the power demand. Therefore, it is possible to meet the electricity demand while suppressing the utility cost.

In claim 3 , since the electric power from the power storage device having a low electric power unit price can be allocated to the electric power demand, the utility cost can be reduced.

In claim 4 , since the electric power from the fuel cell having a low electric power unit price can be used for the electric power demand, the utility cost can be reduced.

In claim 5 , since the electric power from the power storage device having a low electric power unit price can be allocated to the electric power demand, the utility cost can be reduced.

In claim 6 , it is possible to prevent the purchase of commercial electric power even though the electric power demand can be met by the electric power from the power storage device and the electric power from the fuel cell.

The block diagram which showed the structure of the power supply system which concerns on one Embodiment of this invention. The figure which showed the flowchart of the control which concerns on the planning process. The figure which showed the transition of PV electric power and electric power demand by time. The figure which showed the transition of the purchased electric power unit price, PV electric power unit price, and FC power generation unit price by time. The figure which shows the setting method of the target charge amount of each charge timing. (A) The figure which shows the setting method of the full charge time. (B) The figure which shows the correction method of the target charge amount. The figure which showed the flowchart of the control which concerns on execution processing.

Hereinafter, the power supply system 1 according to the embodiment of the present invention will be described with reference to FIG.

The power supply system 1 is provided in a house or the like, and supplies power from a commercial power source S, a fuel cell 20 described later, or the like to a load (not shown). The power supply system 1 mainly includes a photovoltaic power generation unit 10, a fuel cell 20, a power storage device 30, a distribution board 40, and a control device 50.

The photovoltaic power generation unit 10 is a device that generates electricity by using sunlight (natural energy). The photovoltaic power generation unit 10 is composed of a solar cell panel (PV) or the like. The photovoltaic power generation unit 10 is installed in a sunny place such as on the roof of a house. The photovoltaic power generation unit 10 is configured to be able to output the generated electric power.

The fuel cell 20 is a fuel cell that is composed of a solid oxide fuel cell (SOFC: Solid Oxide Fuel Cell) or the like and is installed in a house. The fuel cell 20 can generate electricity using the supplied fuel (for example, hydrogen or the like). Further, the fuel cell 20 includes a hot water storage unit (not shown), and hot water can be boiled in the hot water storage unit by using the heat generated during power generation.

The power storage device 30 is a device configured to be able to charge and discharge electric power from the commercial power source S and the solar power generation unit 10. The power storage device 30 uses a storage battery made of a lithium ion battery, a nickel hydrogen battery, or the like capable of charging and discharging power, a charger that rectifies the supplied AC power to charge the storage battery, and DC power from the storage battery. It is equipped with an inverter or the like that converts it into AC power and outputs it.

The distribution board 40 distributes the electric power supplied from the electric power supply source to the load according to the power consumption of the load. The distribution board 40 is composed of a leakage breaker (not shown), a molded case circuit breaker, a control unit, and the like. The distribution board 40 is connected to a commercial power source S as a power supply source, a solar power generation unit 10, a fuel cell 20, and a power storage device 30, and power is appropriately supplied from these.

In the present embodiment, the load is a circuit connected to an electric appliance or the like that consumes electric power in a house. The load is provided for each room or for each outlet dedicated to a device that consumes a large amount of electric power such as an air conditioner, and is connected to the distribution board 40 (not shown).

The control device 50 manages the information in the power supply system 1 and controls the power supply mode in the power supply system 1, for example, the power generation of the fuel cell 20 and the charging / discharging of the power storage device 30. The control device 50 is composed of a storage unit such as a RAM or a ROM, an arithmetic processing unit such as a CPU, or the like.

The control device 50 stores information related to the electric power unit price in the storage unit. Specifically, the control device 50 uses the power purchase unit price (hereinafter referred to as “purchased power unit price”) of the power purchased from the commercial power source S (hereinafter referred to as “purchased power”) and solar power as information related to the power unit price. The unit price of electricity generated by the power generation unit 10 (hereinafter referred to as "PV power") (hereinafter referred to as "PV unit price"), the unit price of power generation of the fuel cell 20 (hereinafter referred to as the unit price of fuel required for power generation of the fuel cell 20). (Hereinafter, referred to as "FC power generation unit price") is memorized.

The control device 50 stores the purchased power unit price when the power storage device 30 is charged with the purchased power. Further, the control device 50 stores the PV power unit price when the PV power is charged to the power storage device 30.

The control device 50 stores data (actual results) of load power consumption (power demand) for each hour in the storage unit. Further, the control device 50 accumulates data (actual results) of PV power for each hour. The control device 50 predicts future power demand and PV power amount based on these accumulated data.

The control device 50 charges the power storage device 30 based on the information related to the power unit price, the predicted future power demand, and the PV power (hereinafter, referred to as “charging timing”), and the charging timing. At the end of the process, a planning process is performed to plan the amount of electric power to be stored in the power storage device 30 (hereinafter, referred to as “target charge amount”). Further, the control device 50 determines from which power source (commercial power source S, fuel cell 20 or power storage device 30) to supply power to the load in response to the power demand, and performs an execution process of actually supplying power. conduct.

The configuration of the "control device" according to the present invention is not limited to the configuration of the control device 50. For example, the "control device" according to the present invention may be composed of a control unit of the power storage device 30 and a control unit of the fuel cell 20.

Hereinafter, control related to the planning process by the control device 50 will be described with reference to FIGS. 2 to 6. The hourly transition of PV power and power demand shown in FIG. 3 and the hourly transition of the purchased power unit price and PV power unit price shown in FIG. 4 were predicted by the control device 50 based on past results and the like. It is a thing.

Further, in FIG. 4, the power unit price is shown by a polygonal line for convenience, but the power unit price shown at the time t (for example, 6 o'clock) is the power unit price in the t hour range (for example, 6 o'clock).

As shown in FIG. 2, in step S10, the control device 50 sets the charging timing. In this step, the control device 50 sets the time zone (first time zone) in which the PV surplus power (PV power surplus with respect to the power demand) is generated as the first charging timing. Further, the control device 50 sets the time zone (second time zone) at which the purchase power unit price is the minimum as the second charging timing. Further, the control device 50 sets a time zone (third time zone) in which the purchased power unit price is less than the PV power unit price as the third charging timing.

In the example shown in FIG. 3, the PV power exceeds the power demand between 9 and 16 o'clock, and the PV surplus power is generated. Therefore, the control device 50 sets the 9 to 16 o'clock range (first time zone) as the first charging timing.

Further, in the example shown in FIG. 4, the unit price of purchased electric power is the lowest between 3 and 6 o'clock. Therefore, the control device 50 sets the 3 to 6 o'clock range (second time zone) as the second charging timing.

Further, in the example shown in FIG. 4, the purchased power unit price is less than the PV power unit price between 21:00 and 6:00. Therefore, the control device 50 sets the third time zone from 21:00 to 2:00 (third time zone) excluding the portion overlapping with the second time zone (3 to 6:00). Set as charging timing.

The control device 50 proceeds to step S12 after performing the process of step S10.

In step S12, the control device 50 sets the priority of the charging timing. In this step, the control device 50 preferentially charges the power storage device 30 at which charging timing (time zone) of the charging timings (first to third time zones) (target charge amount is increased). Decide whether to modify (increase). The control device 50 sets the priority of the charging timing in ascending order of the unit price of electric power at the time of charging. Specifically, the control device 50 has a PV power unit price in the 9 to 16 o'clock range (first time zone), a purchased power unit price in the 3 to 6 o'clock range (second time zone), and a purchased power unit price in the 21 to 2 o'clock range. Priority is set for the purchased power unit price in (third time zone) in ascending order of unit price.

In the example shown in FIG. 4, the purchase power unit price in the 3 to 6 o'clock range (second time zone), the purchase power unit price in the 21:00 to 2 o'clock range (third time zone), and the purchase power unit price in the 9 to 16:00 range (first time zone). Since the unit price of PV power is lower in the order of PV power unit price (time zone), 3 to 6 o'clock (second time zone) is the first priority, and 21 to 2 o'clock (third time zone) is. The second priority is the second priority, and the 9 to 16 o'clock range (first time zone) is the third priority.

The control device 50 proceeds to step S14 after performing the process of step S12.

In step S14, the control device 50 sets the target charge amount at each charge timing. In this step, the control device 50 calculates the purchased power amount (that is, the amount that the PV power amount cannot cover with respect to the power demand amount) during each charging timing. Then, the control device 50 sets the purchased power amount between each (calculated) charging timing (end point) to the next charging timing as the target charging amount of each charging timing. At this time, when the target charge amount exceeds the storage capacity (maximum capacity) of the power storage device 30, the control device 50 sets the target charge amount as the maximum capacity.

As shown in FIG. 5, the target charge amount in the 3 to 6 o'clock range (second time zone) is the period (7 to 8) until the next charging timing, the 9 to 16 o'clock range (first time zone). It is set to 1.5 kWh (the amount of power corresponding to the region indicated by H1 in FIGS. 3 and 5), which is the purchased power amount in the time zone). In addition, the target charge amount in the 9 to 16 o'clock range (first time zone) is the purchase during the period (17:00 to 20:00 range) from 21:00 to 2 o'clock (third time zone), which is the next charging timing. The electric energy is set to 7.5 kWh (the electric energy corresponding to the region indicated by H2 in FIGS. 3 and 5). In addition, the target charge amount in the 21:00 to 2 o'clock range (third time zone) is set to 0 kWh because there is no period until the next charging timing, the 3 to 6 o'clock range (second time zone). To. Note that, in FIG. 5 and FIG. 6 described below, the target charge amount at the end of the charge timing is conceptually shown. For example, in the 3 to 6 o'clock range (second time zone), 3 to 6 It indicates that the entire time zone is charged at 1.5 kWh, and does not indicate that the battery is charged at 1.5 kWh every hour.

As a result, the electric power demand until the next charging timing can be covered by the electric power discharged from the power storage device 30. The control device 50 proceeds to step S16 after performing the process of step S14.

In step S16, the control device 50 sets the full charge time (charging timing in which the target charge amount is the storage capacity of the power storage device 30). In this step, the control device 50 corrects the target charge amount of the charge timing having the first highest priority (highest priority) set in step S12 to the storage capacity of the power storage device 30.

For example, assuming that the storage capacity of the power storage device 30 is 10 kWh, as shown in FIG. 6A, the control device 50 has a charge timing of the first priority, which is in the 3 to 6 o'clock range (second time zone). The target charge amount in the above is corrected to 10 kWh, which is the storage capacity of the power storage device 30 (see FIGS. 5 and 6A).

As a result, a large amount of electric power having a low unit price can be charged, so that the utility cost can be reduced. The control device 50 proceeds to step S18 after performing the process of step S16.

In step S18, the control device 50 determines whether or not the chargeable amount> the target charge amount. Here, the chargeable amount is the amount of electric power when the power storage device 30 is charged with the maximum input power (maximum capacity) in the entire charging timing time zone.

When the control device 50 determines that the chargeable amount> the target charge amount (“YES” in step S18), the control device 50 ends the control related to the planning process shown in FIG. On the other hand, when the control device 50 determines that the chargeable amount> the target charge amount is not satisfied (“NO” in step S18), the control device 50 proceeds to step S20.

The case of "NO" in step S18 indicates a case where the target charge amount is not reached even if the charge is performed with the maximum input power of the power storage device 30 at the charge timing of the first priority. For example, if the maximum input power of the power storage device 30 is 2 kW and the target charge amount in the 3 to 6 o'clock range (second time zone), which is the charge timing of the first priority, is 10 kWh, the charge timing is the first priority. The chargeable amount of the power storage device 30 at the charging timing of 3 to 6 o'clock (second time zone) is 2 kW × 4 h = 8 kWh, which is 2 kWh short of the target charge amount (10 kWh).

In step S20, the control device 50 has a shortage with respect to the target charge amount in the 3 to 6 o'clock range (second time zone), which is the first priority, that is, the chargeable amount (8 kWh) from the target charge amount (10 kWh). The value obtained by subtracting (2kWh) is added (distributed) to the target charge amount in the 21:00 to 2 o'clock range (third time zone), which is the second highest priority.

As a result, the power storage device 30 can be filled with inexpensive electric power, and the overall utility cost can be suppressed. After performing the process of step S20, the control device 50 ends the control related to the planning process shown in FIG.

By performing the control related to the planning process as described above, the PV surplus power can be charged, and the power storage device 30 can be charged with a lower unit price (cheap) power according to the purchased power amount. Costs can be reduced.

Next, the control related to the execution process by the control device 50 will be described with reference to FIGS. 3, 4 and 7.

As shown in FIG. 7, in step S28, the control device 50 determines whether or not the current charging timing is reached. The charging timing is determined by the control related to the planning process shown in FIG. 2 (see FIGS. 3 and 4).

When the control device 50 determines that the current charging timing is (“YES” in step S28), the control device 50 proceeds to step S30.

In step S30, the control device 50 determines whether or not the remaining charge amount> the target charge amount. The remaining amount of electricity stored is the current amount of electric power stored in the electricity storage device 30. The target charge amount is determined by the control related to the planning process shown in FIG. 2 (see FIG. 6B).

When the control device 50 determines that the remaining charge amount does not equal the target charge amount (“NO” in step S30), the control device 50 proceeds to step S32. On the other hand, when it is determined that the remaining charge amount> the target charge amount (“YES” in step S30), the control device 50 ends the control related to the execution process shown in FIG. 7.

The case of "NO" in step S30 indicates that the remaining charge amount has not reached the target charge amount and the power storage device 30 needs to be charged. On the other hand, the case of "YES" in step S30 indicates that the remaining charge amount has reached the target charge amount and the power storage device 30 does not need to be charged.

In step S32, the control device 50 determines whether or not the FC power generation unit price <purchased power unit price or PV power unit price. Specifically, the control device 50 currently has a second time zone (3 to 6 o'clock) when the purchased power unit price is the minimum, or a third time zone (3 to 6 o'clock) when the purchased power unit price is less than the PV power unit price ( In the case of 21:00 to 2:00), it is determined whether or not the FC power generation unit price <purchased power unit price. Further, the control device 50 determines whether or not the FC power generation unit price <PV power unit price when the present time is the first time zone (9 to 16:00) when the PV surplus power is generated.

When the control device 50 determines that the FC power generation unit price <purchased power unit price or PV power unit price (“YES” in step S32), the control device 50 proceeds to step S34. On the other hand, when the control device 50 determines that the FC power generation unit price <purchased power unit price or PV power unit price (“NO” in step S32), the control device 50 proceeds to step S36.

In step S34, the control device 50 generates electricity for the fuel cell 20. The control device 50 generates electricity in the fuel cell 20 according to the electric power demand.

In the example shown in FIG. 4, the control device 50 generates the fuel cell 20 according to the power demand in the 9 to 16 o'clock range (first time zone) where the FC power generation unit price <PV power unit price. Further, the control device 50 causes the fuel cell 20 to generate power according to the power demand in the range of 21:00 to 2:00 (third time zone) where the FC power generation unit price <purchased power unit price.

In this way, by allocating the electric power generated by the fuel cell 20 having a low unit price of electric power (hereinafter referred to as "FC electric power"" to the electric power demand, the amount of electric power purchased can be reduced and the utility cost can be reduced. ..

The control device 50 proceeds to step S36 after performing the process of step S34.

In step S36, the control device 50 charges the power storage device 30. The control device 50 charges the power storage device 30 at the charging timing and the target charge amount determined by the control related to the planning process shown in FIG. 2 (see FIG. 6B).

In the examples shown in FIGS. 3 and 4, the control device 50 has a target charge amount of 10 kWh in the 3 to 6 o'clock range (second time zone) when the remaining charge of the power storage device 30 is the target charge amount (FIG. 6 (b)). The power storage device 30 is charged with the purchased electric power so as to be (see). Further, in the control device 50, the remaining charge amount of the power storage device 30 is 7.5 kWh (see FIGS. 6 (a) and 6 (b)) in the 9 to 16 o'clock range (first time zone). ), The power storage device 30 is charged with the surplus PV power. Further, the control device 50 purchases power so that the remaining charge amount of the power storage device 30 becomes 2 kWh (see FIG. 6B), which is the target charge amount, between 21:00 and 2 o'clock (third time zone). Charges the power storage device 30.

In addition, even if the target charge amount is not reached even if all of the PV surplus power is charged in the 9 to 16 o'clock range (first time zone) when the PV surplus power is generated, the control device 50 is used for the PV. Do not charge more than the surplus power (charge with purchased power).

The control device 50 proceeds to step S38 after performing the process of step S36.

In step S38, the control device 50 performs the charge unit price update process. In this process, the control device 50 updates the charge unit price, which is the average unit price of the electric power charged in the power storage device 30. The control device 50 updates the charge unit price, for example, every hour.

The charge unit price P _t [yen / kWh] at time t is updated (calculated) by the following equation 1.
(Equation 1) P _t = (P _t-1 x E _b + P _c x E _c ) / (E _b + E _c )
Here, P _t-1 is the charge unit price [yen / kWh] updated at the time t-1, E _b is the remaining charge [kWh] at the time t-1, and P _c is the time t-1. The unit price of charging power [yen / kWh] from time to time t, and _Ec indicate the amount of charge [kWh] from time t-1 to time t.

For example, the updated charge unit price at 21:00 is 20 [yen / kWh], the remaining charge at 21:00 is 4 kWh, and the charge power unit price between 21:00 and 22:00 is 40 [yen / kWh], 21 ~. Assuming that the charge amount during 22:00 is 1 kWh, the charge unit price P ₂₂ at 22:00 is calculated as follows.
P ₂₂ = (20 [yen / kWh] x 4 [kWh] + 40 [yen / kWh] x 1 [kWh]) / (4 [kWh] + 1 [kWh]) = 24 [yen / kWh]

See step S28 again. When the control device 50 determines that the current timing is not the charging timing (“NO” in step S28), the control device 50 proceeds to step S40.

In step S40, the control device 50 determines whether or not the charge unit price <purchased power unit price. The control device 50 makes this determination by comparing the immediately preceding charging unit price with the current purchased power unit price.

When the control device 50 determines that the charge unit price <purchased power unit price (“YES” in step S40), the control device 50 proceeds to step S46. On the other hand, when the control device 50 determines that the charge unit price <purchased power unit price does not exist (“NO” in step S40), the control device 50 proceeds to step S42.

The case of "NO" in step S40 indicates that the charge unit price is not cheaper than the purchased power unit price, and no cost merit can be obtained even if the power storage device 30 is discharged according to the power demand. Therefore, in the case of "NO" in step S40, the power storage device 30 is not discharged in the following steps. On the other hand, the case of "YES" in step S40 indicates that the charge unit price is lower than the purchased power unit price, and the cost merit can be obtained by discharging the power storage device 30 according to the power demand. Therefore, if "YES" in step S40, it is considered to discharge the power storage device 30 in the following steps.

In step S42, the control device 50 determines whether or not the FC power generation unit price <purchased power unit price. The control device 50 makes this determination by comparing the FC power generation unit price and the purchased power unit price at the current time.

When the control device 50 determines that the FC power generation unit price <purchased power unit price (“YES” in step S42), the control device 50 proceeds to step S44. On the other hand, when it is determined that the FC power generation unit price does not equal the purchased power unit price (“NO” in step S42), the control device 50 ends the control related to the execution process shown in FIG. 7.

The case of "NO" in step S42 indicates that the FC power generation unit price is not cheaper than the purchased power unit price, and no cost merit can be obtained even if the fuel cell 20 is generated according to the power demand. Therefore, in the case of "NO" in step S42, the fuel cell 20 is not generated in the following steps.

In step S44, the control device 50 generates electricity for the fuel cell 20. The control device 50 generates electricity in the fuel cell 20 according to the electric power demand. In this way, by allocating FC power having a low unit price to power demand, the amount of purchased power can be reduced and the utility cost can be reduced.

After performing the process of step S44, the control device 50 ends the control related to the execution process shown in FIG. 7.

On the other hand, in step S46, the control device 50 determines whether or not the FC power generation unit price <purchased power unit price. The control device 50 makes this determination by comparing the current FC power generation unit price with the purchased power unit price.

When the control device 50 determines that the FC power generation unit price <purchased power unit price (“YES” in step S46), the control device 50 proceeds to step S50. On the other hand, when the control device 50 determines that the charge unit price <purchased power unit price does not exist (“NO” in step S46), the control device 50 proceeds to step S48.

The case of "NO" in step S46 indicates that the FC power generation unit price is not cheaper than the purchased power unit price, and the cost merit cannot be obtained even if the fuel cell 20 is generated. Therefore, in the case of "NO" in step S46, the fuel cell 20 is not generated in the following steps. On the other hand, the case of "YES" in step S46 indicates that the FC power generation unit price is lower than the purchased power unit price, and the cost merit can be obtained by generating the fuel cell 20. Therefore, in the case of "YES" in step S46, it is considered to generate power of the fuel cell 20 in the following steps.

In step S48, the control device 50 discharges the power storage device 30. The control device 50 discharges the power storage device 30 according to the power demand. By discharging the charging power having a low unit price in this way, the amount of purchased power can be reduced and the utility cost can be reduced.

After performing the process of step S48, the control device 50 ends the control related to the execution process shown in FIG. 7.

In step S50, the control device 50 determines whether or not the FC power generation unit price <charge unit price. The control device 50 makes this determination by comparing the current FC power generation unit price with the immediately preceding charge unit price.

When the control device 50 determines that the FC power generation unit price <charge unit price (“YES” in step S50), the control device 50 proceeds to step S52. On the other hand, when the control device 50 determines that the FC power generation unit price <charge unit price does not exist (“NO” in step S50), the control device 50 proceeds to step S58.

The case of "NO" in step S50 indicates that the FC power generation unit price is not cheaper than the charge unit price, and that the cost merit can be obtained by discharging the fuel cell 20 from the power storage device 30 rather than generating the power. There is. On the other hand, the case of "YES" in step S50 indicates that the FC power generation unit price is cheaper than the charge unit price, and that the cost merit can be obtained by generating the fuel cell 20 rather than discharging it from the power storage device 30. ..

In step S52, the control device 50 generates electricity for the fuel cell 20. The control device 50 generates electricity in the fuel cell 20 according to the electric power demand. The control device 50 proceeds to step S54 after performing the process of step S52.

In step S54, the control device 50 determines whether or not the power demand-FC power (value obtained by subtracting the FC power from the power demand, that is, the purchased power)> α. α can be a predetermined value, for example, 0.1 kW.

When the control device 50 determines that the power demand −FC power> α (“YES” in step S54), the control device 50 proceeds to step S56. On the other hand, when it is determined that the power demand −FC power> α is not satisfied (“NO” in step S54), the control device 50 ends the control related to the execution process shown in FIG.

The case of "NO" in step S54 indicates that most of the electric power demand can be covered by FC electric power. On the other hand, the case of "YES" in step S54 indicates that FC electric power cannot cover most of the electric power demand.

In step S56, the control device 50 discharges the power storage device 30. The control device 50 discharges the power storage device 30 according to the power demand.

In this way, the FC power having the lowest unit price is first generated (see step S52), and then the charging power having the lowest unit price is discharged from the power storage device 30 (see step S56) as needed. The amount of electric power can be reduced, and the utility cost can be reduced.

After performing the process of step S56, the control device 50 ends the control related to the execution process shown in FIG. 7.

On the other hand, in step S58, the control device 50 determines whether or not the amount of power demand until the next charge> the remaining amount of electricity stored. The control device 50 makes this determination by comparing the predicted power demand from the present to the next charging timing with the current remaining charge.

When the control device 50 determines that the amount of power demand until the next charge> the remaining amount of electricity stored (“YES” in step S58), the control device 50 proceeds to step S60. On the other hand, when the control device 50 determines that the power demand amount until the next charge> the remaining charge amount (“NO” in step S58), the control device 50 proceeds to step S62.

In step S60, the control device 50 performs the discharge amount adjusting process. The control device 50 averages the discharge amount of the power storage device 30 at each time until the next charging timing.

Specifically, for example, when the current remaining charge is 3 kWh and there is 3 hours until the next charging timing, the control device 50 demands electricity even if the power demand for the first hour is 3 kWh. Instead of discharging the entire remaining amount of electricity (3 kWh) in the first hour in order to cover the amount, the electricity storage device 30 discharges 1 kWh per hour.

The control device 50 proceeds to step S62 after performing the process of step S60.

In step S62, the control device 50 discharges the power storage device 30. The control device 50 discharges the power storage device 30 with the discharge amount adjusted in step S60. The control device 50 proceeds to step S64 after performing the process of step S62.

In step S64, the control device 50 determines whether or not power demand-discharge power (value obtained by subtracting the discharge power of the power storage device 30 from the power demand, that is, purchased power)> β. β can be a predetermined value, for example, 0.35 kW.

In step S66, the control device 50 generates electricity for the fuel cell 20. The control device 50 generates electricity in the fuel cell 20 according to the electric power demand. After performing the process of step S66, the control device 50 ends the control related to the execution process shown in FIG. 7.

In this way, the charging power having the lowest electric energy unit price is first discharged from the power storage device 30 (see step S62), and then the FC electric power having the lowest electric energy unit price is generated as needed (see step S66). The amount of electric power can be reduced, and the utility cost can be reduced.

As described above, in the power supply system 1 according to the present embodiment, the power storage device 30 and the fuel cell 20 can be optimally operated for any combination of the PV power unit price, the purchased power unit price, and the FC power generation unit price, and the utility cost can be reduced. It can be reduced. In addition, even if the PV power unit price, purchased power unit price, and FC power generation unit price fluctuate depending on the season or time, cheap power can be preferentially supplied to the load, so utility costs can be reduced. Become.

As described above, the power supply system 1 according to the present embodiment is a solar power generation unit 10 (power generation unit) capable of generating power by using natural energy and selling the generated power to the commercial power source S. A power storage device 30 capable of charging / discharging purchased power (commercial power from the commercial power source S) and PV power (power generated from the solar power generation unit 10), and a control for controlling charging / discharging of the power storage device 30. The control device 50 includes a device 50 (control unit), and the control device 50 is a unit price of power purchased at the time of charging the power storage device 30 (a unit price of power purchased at the time of charging). , And the charge unit price, which is the average unit price of the charged power, is calculated based on the PV power unit price when the power storage device 30 is charged (the unit price of the PV power sold). Then, the charge / discharge of the power storage device 30 is controlled based on the calculated charge unit price.
With such a configuration, it is possible to reduce the utility cost according to the fluctuation of the electric power unit price.

Further, in the power supply system 1 according to the present embodiment, the control device 50 can execute a planning process for determining a charging timing, which is a time zone in which the power storage device 30 can be charged. Predict the first time zone when the surplus of PV power is generated with respect to the demand, the second time zone when the purchased power unit price is the minimum, or the third time zone when the purchased power unit price is less than the PV power unit price. Then, the predicted first time zone, the second time zone, and the third time zone are set as the charging timing.
With this configuration, the power storage device 30 can be charged at the timing when the PV surplus power is generated or at the timing when the power unit price of the power to be charged is low.

Further, in the planning process, the control device 50 can determine a target charge amount, which is a charge amount to be charged to the power storage device 30, at each of the charge timings, and is one of the charge timings, the first charge. The power demand from the timing to the second charge timing, which is the next charge timing of the first charge timing, and the power generation amount of the solar power generation unit 10 are predicted, and based on the predicted power demand and the power generation amount, the above It determines the target charge amount at the first charge timing.
With this configuration, the power demand until the next charging timing (second charging timing) can be met by the power discharged from the power storage device 30.

Further, in the planning process, the control device 50 has the power selling unit price at the time of charging in the first time zone, the power purchasing unit price at the time of charging in the second time zone, and the power purchasing unit price at the time of the third time zone. The priority is set in ascending order of unit price with respect to the power purchase unit price at the time of charging, and the target charge amount at the charging timing having the highest priority is corrected to the maximum capacity of the power storage device 30.
With such a configuration, a large amount of electric power having a low unit price of electric power can be charged, so that the utility cost can be reduced.

Further, in the planning process, when the control device 50 does not reach the maximum capacity even if it is charged with the maximum capacity of the power storage device 30 at the charging timing having the highest priority, the priority is second. The shortage is added to the target charge amount at the higher charge timing.
With this configuration, even if the power charged at the charging timing with the lowest power unit price cannot meet the power demand until the next charging timing, the power is charged at the charging timing with the second lowest power unit price. Since it is possible to meet the power demand with the generated power, it is possible to meet the power demand while suppressing the utility cost.

Further, when the charging unit price is lower than the current purchased power unit price, the control device 50 discharges the power storage device 30 according to the power demand.
With such a configuration, the electric power from the power storage device 30 having a low electric power unit price can be allocated to the electric power demand, so that the utility cost can be reduced.

Further, the control device 50 includes a fuel cell 20 capable of generating electricity by using fuel, and when the power generation unit price of the fuel cell 20 is lower than the charging unit price and the current purchased power unit price, the fuel cell 20 Is to generate electricity.
With such a configuration, the electric power from the fuel cell 20 having a low electric power unit price can be allocated to the electric power demand, so that the utility cost can be reduced.

Further, the control device 50 discharges the power storage device 30 when the charge unit price is lower than the power generation unit price of the fuel cell 20 and the current purchased power unit price.
With such a configuration, the electric power from the power storage device 30 having a low electric power unit price can be allocated to the electric power demand, so that the utility cost can be reduced.

Further, in the control device 50, the charging unit price is lower than the power generation unit price of the fuel cell 20 and the current purchased power unit price, and the power generation unit price of the fuel cell 20 is higher than the current purchased power unit price. When it is low, the power storage device 30 is discharged so that the discharge amount of the power storage device 30 at each time is averaged, and the averaged discharge amount cannot cover all or part of the predicted power demand. In this case, the fuel cell 20 is generated to generate electricity.
With this configuration, it is possible to prevent the purchase of commercial power even though the power demand from the power storage device 30 (discharge power) and the power from the fuel cell 20 (FC power) can be met. be able to.

The solar power generation unit 10 according to this embodiment is an embodiment of the power generation unit.
Further, the control device 50 according to the present embodiment is an embodiment of the control unit.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above configuration, and various modifications can be made within the scope of the invention described in the claims.

For example, in the present embodiment, the power supply system 1 is provided with the fuel cell 20, but the fuel cell 20 may not necessarily be provided.

Further, in step S14 shown in FIG. 2, when the FC power generation unit price is lower than the purchased power unit price, the control device 50 targets the amount obtained by subtracting the FC power amount from the purchased power amount in consideration of the FC power. It may be set to the amount.

Further, in the present embodiment, the threshold value α used in the determination in step S54 shown in FIG. 7 is assumed to be 0.1 kW, but can be any value, for example, 0 kW. However, if it is not desired to sell FC power due to reasons such as the unit price of power being reduced, it is desirable that α is a value larger than 0 as in the present embodiment.

Further, in the present embodiment, the threshold value β used in the determination in step S64 shown in FIG. 7 is set to 0.35 kW, but it can be any value, for example, 0 kW. However, considering the decrease in efficiency associated with operating the fuel cell 20 to cover a small amount of electric power, β is preferably set to a value larger than 0 as in the present embodiment.

1 Power supply system 10 Solar power generation unit 20 Fuel cell 30 Power storage device 50 Control device

Claims (6)

A power generation unit that can generate electricity using natural energy and sell the generated power to commercial power sources.
A power storage device capable of charging and discharging the commercial power from the commercial power source and the generated power from the power generation unit,
A control unit that controls charging and discharging of the power storage device,
Equipped with
The control unit
The charge-time power purchase unit price, which is the power purchase unit price of the commercial power when the commercial power is charged to the power storage device, and the charge, which is the power sale unit price of the generated power when the generated power is charged to the power storage device. The charge unit price, which is the average unit price of the charged electric power, is calculated based on the hourly power sale unit price, and the charge / discharge of the power storage device is controlled based on the calculated charge unit price .
It is possible to execute a planning process for determining the charging timing, which is the time zone in which the power storage device can be charged.
In the planning process
The first time zone in which the surplus of the generated power is generated with respect to the power demand, the second time zone in which the purchase unit price of the commercial power is the minimum, or the power purchase unit price of the commercial power is the sale of the generated power. A third time zone that is less than the unit price of electricity is predicted, and the predicted first time zone, the second time zone, and the third time zone are set as the charging timing.
It is possible to determine the target charge amount, which is the charge amount to be charged to the power storage device, at each of the charge timings.
The power demand from the first charge timing, which is one of the charge timings, to the second charge timing, which is the next charge timing after the first charge timing, and the power generation amount of the power generation unit are predicted, and the predicted power demand and the predicted power demand and the power generation amount of the power generation unit are predicted. Based on the power generation amount, the target charge amount at the first charge timing is determined.
The unit price is in ascending order with respect to the unit price of electricity sold during charging in the first time zone, the unit price of electricity purchased during charging in the second time zone, and the unit price of electricity purchased during charging in the third time zone. Set priorities and
The target charge amount at the charge timing having the highest priority is corrected to the maximum capacity of the power storage device.
Power supply system. The control unit
In the planning process
If the maximum capacity is not reached even if charging is performed with the maximum capacity of the power storage device at the charging timing having the highest priority, the amount short of the target charge amount at the charging timing having the second highest priority is insufficient. To add,
The power supply system according to claim 1. The control unit
When the charge unit price is lower than the current purchase unit price of the commercial power, the power storage device is discharged according to the power demand.
The power supply system according to claim 1 or 2 . Equipped with a fuel cell that can generate electricity using fuel,
The control unit
When the power generation unit price of the fuel cell is lower than the charge unit price and the current power purchase unit price of the commercial power, the fuel cell is generated to generate power.
The power supply system according to any one of claims 1 to 3 . The control unit
When the charge unit price is lower than the power generation unit price of the fuel cell and the current power purchase unit price of the commercial power, the power storage device is discharged.
The power supply system according to claim 4. The control unit
When the charge unit price is lower than the power generation unit price of the fuel cell and the current power purchase unit price of the commercial power, and the power generation unit price of the fuel cell is lower than the current power purchase unit price of the commercial power.
The power storage device is discharged so that the discharge amount of the power storage device at each time is averaged.
If the averaged discharge amount cannot meet all or part of the predicted power demand, the fuel cell is generated.
The power supply system according to claim 5 .

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