JP2019170102A - Power supply system - Google Patents

Abstract

To provide a power supply system capable of reducing energy costs in accordance with variation of electric power unit prices.SOLUTION: A power supply system 1 includes: a solar power generation unit 10 capable of generating electric power by using natural energy and capable of selling the generated electric power to a commercial power supply S; a power storage apparatus 30 capable of charging/discharging purchased electric power (commercial electric power from the commercial power supply S) and PV power (generated electric power from the solar power generation unit 10); and a control device 50 for controlling charging/discharging of the power storage apparatus 30. The control device 50 calculates a charging unit price to be an average unit price of charged electric power on the basis of a purchased electric power unit price at charging to be a power purchase unit price of purchased electric power at charging the purchased electric power to the power storage apparatus 30 and a PV power unit price at charging to be a power selling unit price of PV electric power at charging PV power to the power storage apparatus 30 and controls charging/discharging of the power storage apparatus 30 on the basis of the calculated charging unit price.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technique of a power supply system including a power storage device that can charge and discharge power from a power generation unit.

  Conventionally, a technique of a power supply system including a power storage device that can charge and discharge power from a power generation unit has been publicly known. For example, as described in Patent Document 1.

  Patent Document 1 describes a power supply system that includes a solar power generation unit and a power storage device that can charge and discharge power from the solar power generation unit. The power supply system is configured to reversely flow (sell power) surplus power from the photovoltaic power generation unit to a commercial power source, and to charge the power storage device with midnight power with a low power unit price. Yes. Thereby, reduction of a utility bill can be aimed at.

  However, the unit price of solar power generation has been decreasing in recent years, and may be lower than the daytime power price, for example. For this reason, in the power supply system described in Patent Document 1, when there is such a change in the unit price of electric power, there are cases where the utility cost cannot be minimized.

JP 2014-45635 A

  This invention is made | formed in view of the above situations, The subject which it is going to solve is providing the electric power supply system which can aim at reduction of a utility bill according to the fluctuation | variation of a power unit price.

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

  That is, in claim 1, a power generation unit that can generate power using natural energy and can sell the generated power to a commercial power source, commercial power from the commercial power source, and power generation unit from the power generation unit A power storage device capable of charging / discharging the generated power; and a control unit that controls charging / discharging of the power storage device, wherein the control unit purchases the commercial power when the power storage device is charged with the commercial power. Charging that is the average unit price of the charged power, based on the unit price of electricity purchased during charging that is the unit price of electricity and the unit price of selling electricity that is the unit price of electricity sold when the power storage device is charged with the generated power A unit price is calculated, and charge / discharge of the power storage device is controlled based on the calculated unit charge price.

  In Claim 2, the said control part can perform the plan process which determines the charge timing which is a time slot | zone which can charge the said electrical storage apparatus, In the said plan process, the surplus of the said generated electric power with respect to an electric power demand The first time zone in which power generation occurs, the second time zone in which the unit price of commercial power is minimized, or the third time period in which the unit price of commercial power is less than the unit price of power generated And the predicted first time zone, second time zone, and third time zone are set as the charging timing.

  In the present invention, the control unit can determine a target charge amount that is a charge amount to be charged in the power storage device at each of the charge timings in the planning process, and is one of the charge timings. Predicting the power demand from the one charging timing to the second charging timing that is the charging timing next to the first charging timing and the power generation amount of the power generation unit, based on the predicted power demand and the power generation amount, The target charge amount at one charge timing is determined.

  5. The control unit according to claim 4, wherein in the planning process, the charging unit price at the time of charging in the first time zone, the power unit price at the time of charging in the second time zone, and the third time period. A priority is set in order from the lowest unit price with respect to the power purchase unit price during charging in a belt, and the target charge amount at the charge timing with the highest priority is corrected to the maximum capacity of the power storage device. is there.

  The control unit according to claim 5, wherein, in the planning process, if the priority is not reached even when the maximum capacity of the power storage device is charged at the charging timing with the highest priority, the priority is The shortage is added to the target charge amount at the second highest charge timing.

  According to a sixth aspect of the present invention, when the unit price of charging is lower than the current unit price of commercial power, the control unit discharges the power storage device according to power demand.

  In claim 7, comprising a fuel cell capable of generating power using fuel, the control unit, when the unit price of power generation of the fuel cell is lower than the unit price of charging and the unit price of power purchased of the current commercial power, The fuel cell generates power.

  According to an eighth aspect of the present invention, the control unit discharges the power storage device when the unit price of charging is lower than the unit price of power generation of the fuel cell and the current unit price of purchased commercial power.

  The control unit according to claim 9, wherein 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 the current commercial unit price. When the unit price of power is lower than the unit price of power purchase, the power storage device is discharged so that the discharge amount of the power storage device at each time is averaged, and all or one of the predicted power demand is predicted by the averaged discharge amount. When the portion cannot be covered, the fuel cell is caused to generate power.

  As effects of the present invention, the following effects can be obtained.

  In claim 1, the utility cost can be reduced according to the fluctuation of the unit price of electric power.

  According to the second aspect, the power storage device can be charged at a timing at which surplus power is generated or at a timing at which the unit price of the power to be charged is low.

  In claim 3, the power demand until the next charging timing (second charging timing) can be covered by the power discharged from the power storage device.

  In claim 4, since it is possible to charge a large amount of power with a low power unit price, it is possible to reduce the utility cost.

  In claim 5, even if the power demand cannot be covered only by the power charged at the charging timing with the lowest power unit price, the power demand is covered by the power charged at the charging timing with the second lowest power unit price. Therefore, it is possible to cover the power demand while reducing the utility cost.

  In Claim 6, since the electric power from the electrical storage apparatus with a low electric power unit price can be used for electric power demand, reduction of a utility bill can be aimed at.

  In Claim 7, since the electric power from the fuel cell with a low electric power unit price can be allocated to the electric power demand, the utility cost can be reduced.

  In Claim 8, since the electric power from the electrical storage apparatus with a low electric power unit price can be used for an electric power demand, reduction of an energy bill can be aimed at.

  According to the ninth aspect of the present invention, it is possible to prevent the commercial power from being purchased even though the power demand can be covered by the power from the power storage device and the power from the fuel cell.

The block diagram which showed the structure of the electric power supply system which concerns on one Embodiment of this invention. The figure which showed the flowchart of the control which concerns on a plan process. The figure which showed transition for every hour of PV electric power and electric power demand. The figure which showed the change for every hour of purchased electric power unit price, PV electric power unit price, and FC electric power generation unit price. 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 full charge time. (B) The figure which shows the correction method of target charge amount. The figure which showed the flowchart of the control which concerns on an execution process.

  Below, the electric power supply system 1 which concerns on one Embodiment of this invention is demonstrated using 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 solar power generation unit 10, a fuel cell 20, a power storage device 30, a distribution board 40, and a control device 50.

  The solar power generation unit 10 is a device that generates power using sunlight (natural energy). The photovoltaic power generation unit 10 is configured by 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 solar power generation unit 10 is configured to be able to output the generated power.

  The fuel cell 20 is a fuel cell that is configured by a solid oxide fuel cell (SOFC) or the like and is installed in a house. The fuel cell 20 can generate electric power using supplied fuel (for example, hydrogen). The fuel cell 20 includes a hot water storage unit (not shown), and can boil the hot water in the hot water storage unit using 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 includes a storage battery composed of a lithium ion battery, a nickel metal hydride battery, or the like that can charge and discharge power, a charger that rectifies supplied AC power and charges the storage battery, and direct current power from the storage battery. An inverter for converting to AC power and outputting it is provided.

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

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

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

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

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

  The control device 50 accumulates data (actual results) of load power consumption (power demand) for each hour in the storage unit. Moreover, the control apparatus 50 accumulate | stores the data (result) of PV electric power for every time. The control device 50 predicts the future power demand and the PV power amount based on the accumulated data.

  The control device 50 is configured to charge the power storage device 30 based on the information related to the power unit price, the predicted future power demand and PV power (hereinafter referred to as “charging timing”), and the charging timing. A planning process for planning the amount of power to be stored in the power storage device 30 at the end (hereinafter referred to as “target charge amount”) is performed. Moreover, the control apparatus 50 determines which power source (commercial power supply S, the fuel cell 20, or the electrical storage apparatus 30) should supply electric power with respect to an electric power demand, and performs the execution process which actually supplies electric power. Do.

  Note that 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 configured by a control unit of the power storage device 30 or a control unit of the fuel cell 20.

  Hereinafter, the control related to the planning process by the control device 50 will be described with reference to FIGS. Note that the hourly transition of the PV power and the power demand shown in FIG. 3 and the hourly transition of the purchased power unit price and the PV power unit price shown in FIG. 4 are predicted by the control device 50 based on the past results. Is.

  In FIG. 4, the power unit price is indicated by a broken line for convenience, but the power unit price indicated at the position of time t (for example, 6 o'clock) is the power unit price for 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 a time zone (first time zone) in which PV surplus power (PV power surplus with respect to power demand) is generated as the first charging timing. Moreover, the control apparatus 50 sets the time slot | zone (2nd time slot | zone) where the purchased power unit price becomes the minimum to the 2nd charge timing. Moreover, the control apparatus 50 sets the time slot | zone (3rd time slot | zone) when purchased electric power unit price becomes less than PV electric power unit price to the 3rd charge timing.

  In the example shown in FIG. 3, the PV power exceeds the power demand at 9-16 o'clock, and PV surplus power is generated. Therefore, the control device 50 sets the 9 to 16:00 range (first time zone) as the first charging timing.

  In the example shown in FIG. 4, the purchased power unit price is the lowest at 3 to 6 o'clock. Therefore, the control device 50 sets the 3-6 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 in the 21 to 6 o'clock range. Therefore, the control device 50 sets the 21 to 2 o'clock range (third time zone) to the third time zone except the overlapping portion with the second time zone (3 to 6 o'clock range) of the 21 to 6 o'clock range. Set as charging timing.

  After performing the process of step S10, the control device 50 proceeds to step S12.

  In step S12, the control device 50 sets the priority order of the charging timing. In this step, the control device 50 preferentially charges the power storage device 30 at any charge timing (time zone) among the charge timings (first to third time zones) (the target charge amount is increased upward). Determine whether to correct (increase)). The control device 50 sets the priority order of the charging timing in ascending order of the power unit price during charging. Specifically, the control device 50 includes 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 the 21 to 2 o'clock range. Priorities are set in ascending order of unit price for the purchased power unit price in (third time zone).

  In the example shown in FIG. 4, the purchased power unit price at 3 to 6 o'clock (second time zone), the purchased power unit price at 21 to 2 o'clock (third time zone), and the 9 to 16:00 level (first Because the unit price of PV power is low in the order of the PV power unit price in the time zone of (), the 3rd to 6th hours (second time zone) is the first priority, the 21st to 2nd hours (third time zone) The second highest priority, 9 to 16 o'clock (first time zone) is the third highest priority.

  After performing the process of step S12, the control device 50 proceeds to step S14.

  In step S14, the control device 50 sets a target charge amount at each charge timing. In this step, the control device 50 calculates the purchased power amount between the charging timings (that is, the amount of power demand that cannot be covered by the PV power amount). Then, the control device 50 sets the purchased power amount from (calculated) each charging timing (at the end point) to the next charging timing as the target charging amount at each charging timing. At this time, when the target charge amount exceeds the power 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 range of 3 to 6 o'clock (second time zone) is the period (7 to 8) from 9 to 16:00 in the next charge timing (first time zone). Set to 1.5 kWh (the amount of power corresponding to the area 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 16:00 range (first time zone) is the purchase in the period (17 to 20 o'clock) from the next charge timing to the 21 to 2 o'clock range (third time zone). The power amount is set to 7.5 kWh (the power amount corresponding to the region indicated by H2 in FIGS. 3 and 5). The target charge amount in the 21 to 2 o'clock range (third time zone) is set to 0 kWh because there is no period from the next 3 to 6 o'clock (second time zone), which is the next charging timing. The In addition, in FIG. 5 and FIG. 6 demonstrated below, the target charge amount at the time of completion | finish of a charge timing is shown notionally, For example, in 3-6 o'clock range (second time zone), 3-6 It shows that charging is 1.5 kWh for the entire hour base, and does not indicate charging 1.5 kWh every hour.

  Thereby, the power demand until the next charging timing can be covered by the power discharged from the power storage device 30. After performing the process of step S14, the control device 50 proceeds to step S16.

  In step S <b> 16, control device 50 sets a full charge time (a charging timing with the target charge amount as the storage capacity of power storage device 30). In this step, control device 50 corrects the target charge amount at the charge timing with the first priority (highest rank) set in step S <b> 12 to the power storage capacity of power storage device 30.

  For example, if the power storage capacity of the power storage device 30 is 10 kWh, as shown in FIG. 6A, the control device 50 is in the 3 to 6 o'clock range (second time zone), which is the first priority charging timing. 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 power with a low power unit price can be charged, so that the utility cost can be reduced. After performing the process of step S16, the control device 50 proceeds to step S18.

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

  When it is determined 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 it is determined 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 when charging 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 charging timing of the first priority is 10 kWh, the first priority is the first. The chargeable amount of the power storage device 30 in the 3 to 6 o'clock range (second time zone) as the charging timing is 2 kW × 4h = 8 kWh, which is insufficient by 2 kWh for 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 3rd to 6 o'clock range (second time zone) of the first priority, that is, the chargeable amount (8 kWh) from the target charge amount (10 kWh). Is added (sorted) to the target charge amount in the 21 to 2 o'clock range (third time zone) of the second highest priority order (2 kWh).

  Thereby, the electrical storage apparatus 30 can be filled with inexpensive electric power, and the overall utility cost can be suppressed. The control apparatus 50 complete | finishes control which concerns on the plan process shown in FIG. 2, after performing the process of the said step S20.

  By performing the control related to the planning process as described above, it is possible to charge the PV surplus power, and to charge the power storage device 30 with lower (inexpensive) power according to the purchased power amount. Costs can be reduced.

  Next, control related to execution processing 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 time is the charging timing. The charging timing is determined by the control related to the planning process shown in FIG. 2 (see FIGS. 3 and 4).

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

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

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

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

  In step S32, the control device 50 determines whether or not FC power generation unit price <purchased power unit price or PV power unit price. Specifically, the control device 50 is currently in a second time zone (3 to 6 o'clock) when the purchased power unit price is the minimum, or a third time zone (when the purchased power unit price is less than the PV power unit price). In the case of 21 to 2 o'clock), it is determined whether or not FC power generation unit price <purchased power unit price. Moreover, the control apparatus 50 determines whether it is FC power generation unit price <PV power unit price, when the present is the 1st time slot | zone (9-16 o'clock) in which PV surplus electric power generate | occur | produces.

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

  In step S <b> 34, the control device 50 generates power from the fuel cell 20. The control device 50 causes the fuel cell 20 to generate power according to the power demand.

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

  Thus, by allocating power generated by the fuel cell 20 with a low power unit price (hereinafter referred to as “FC power”) to the power demand, the amount of purchased power can be reduced, and the utility cost can be reduced. .

  After performing the process of step S34, the control device 50 proceeds to step S36.

  In step S <b> 36, control device 50 charges power storage device 30. The control device 50 charges the power storage device 30 at the charge timing and the target charge amount determined by the control related to the planning process shown in FIG. 2 (see FIG. 6B).

  In the example shown in FIGS. 3 and 4, the control device 50 has 10 kWh (FIG. 6B) in which the remaining amount of power stored in the power storage device 30 is the target charge amount at 3 to 6 o'clock (second time zone). The power storage device 30 is charged with the purchased power so that Moreover, the control apparatus 50 is 7.5 kWh (refer FIG. 6 (a) and FIG.6 (b)) whose electrical storage residual amount of the electrical storage apparatus 30 is a target charge amount in a 9 to 16:00 range (1st time slot | zone). ), The power storage device 30 is charged with the PV surplus power. In addition, the control device 50 purchases electric power so that the remaining amount of electricity stored in the electricity storage device 30 is 2 kWh (see FIG. 6B), which is the target charge amount, in the 21 to 2 o'clock range (third time zone). To charge the power storage device 30.

  In addition, even if it is a case where the target charge amount is not reached even if all of the PV surplus power is charged in the 9 to 16:00 range (first time zone) where the PV surplus power is generated, the control device 50 Charging exceeding surplus power (charging with purchased power) is not performed.

  After performing the process of step S36, the control device 50 proceeds to step S38.

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

The charging unit price P _t [yen / kWh] at time t is updated (calculated) by the following equation 1.
(Equation _{1) P t = (P t} -1 × E b + P c × 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 power storage amount [kWh] at the time t-1, and P _c is the time t-1. Unit price [yen / kWh] of charging power from time t to time t, and E _c indicates the charge amount [kWh] from time t−1 to time t.

For example, the charge unit price updated at the time of 21:00 is 20 [yen / kWh], the remaining amount of charge at the time of 21:00 is 4 kWh, the unit price of charge power between 21 to 22:00 is 40 [yen / kWh], 21 to 21 If the charge amount for 22:00 is 1 kWh, the charge unit price P22 for _22:00 is calculated as follows.
P ₂₂ = (20 [yen / kWh] × 4 [kWh] +40 [yen / kWh] × 1 [kWh]) / (4 [kWh] +1 [kWh]) = 24 [yen / kWh]

  Reference is again made to step S28. When it is determined that the current time is not the charging timing (“NO” in step S28), control device 50 proceeds to step S40.

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

  When it is determined that the charging unit price <the purchased power unit price (“YES” in step S40), the control device 50 proceeds to step S46. On the other hand, when it is determined that the charging unit price <the purchased power unit price (“NO” in step S40), the control device 50 proceeds to step S42.

  The case of “NO” in step S40 indicates that the charging unit price is not lower than the purchased power unit price, and that no cost merit is obtained even if the power storage device 30 is discharged according to the power demand. Therefore, if “NO” in the 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 charging unit price is lower than the purchased power unit price, and that the cost merit can be obtained by discharging the power storage device 30 according to the power demand. Therefore, when “YES” in the 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 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 it is determined that the FC power generation unit price <the 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 is less than the purchased power unit price (“NO” in step S42), the control device 50 ends the control related to the execution process shown in FIG.

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

  In step S <b> 44, the control device 50 performs power generation of the fuel cell 20. The control device 50 causes the fuel cell 20 to generate power according to the power demand. Thus, by allocating FC power with a low power unit price to power demand, it is possible to reduce the amount of purchased power and reduce utility costs.

  The control apparatus 50 complete | finishes the control which concerns on the execution process shown in FIG. 7, after performing the process of the said step S44.

  On the other hand, in step S46, the control device 50 determines whether or not 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 it is determined that FC power generation unit price <purchased power unit price (“YES” in step S46), control device 50 proceeds to step S50. On the other hand, when it is determined that the charging unit price <the purchased power unit price is not satisfied (“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 lower than the purchased power unit price, and that no cost merit is obtained even if the fuel cell 20 is generated. Therefore, if “NO” in the 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 that the fuel cell 20 can generate the cost merit. Therefore, if “YES” in the step S46, it is considered that the fuel cell 20 generates power in the following steps.

  In step S <b> 48, control device 50 discharges power storage device 30. Control device 50 discharges power storage device 30 in accordance with the power demand. Thus, by discharging the charging power with a low power unit price, the amount of purchased power can be reduced, and the utility cost can be reduced.

  The control apparatus 50 complete | finishes the control which concerns on the execution process shown in FIG. 7, after performing the process of the said step S48.

  In step S50, the control device 50 determines whether or not 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 charging unit price.

  When it is determined that FC power generation unit price <charge unit price (“YES” in step S50), control device 50 proceeds to step S52. On the other hand, when it is determined that the FC power generation unit price is less than the charging unit price (“NO” in step S50), the control device 50 proceeds to step S58.

  Note that the case of “NO” in step S50 indicates that the FC power generation unit price is not lower than the charge unit price, and that it is possible to obtain cost merit by discharging the power storage device 30 rather than generating the fuel cell 20. Yes. On the other hand, the case of “YES” in step S50 indicates that the FC power generation unit price is lower than the charge unit price, and that the fuel cell 20 generates power more than the power storage device 30 is discharged. .

  In step S <b> 52, the control device 50 performs power generation of the fuel cell 20. The control device 50 causes the fuel cell 20 to generate power according to the power demand. After performing the process of step S52, the control device 50 proceeds to step S54.

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

  When it is determined that power demand−FC power> α (“YES” in step S54), control device 50 proceeds to step S56. On the other hand, when determining 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 power demand can be covered by FC power. On the other hand, the case of “YES” in step S54 indicates that FC power cannot cover most of the power demand.

  In step S <b> 56, control device 50 discharges power storage device 30. Control device 50 discharges power storage device 30 in accordance with the power demand.

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

  The control apparatus 50 complete | finishes the control which concerns on the execution process shown in FIG. 7, after performing the process of the said step S56.

  On the other hand, in step S58, the control device 50 determines whether or not the power demand amount until the next charging> the remaining power storage amount. 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 power storage amount.

  When it is determined that the power demand amount until the next charging> the remaining power storage amount (“YES” in step S58), the control device 50 proceeds to step S60. On the other hand, when it is determined that the power demand amount until the next charging> the remaining power storage amount is not satisfied (“NO” in step S58), the control device 50 proceeds to step S62.

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

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

  After performing the process of step S60, the control device 50 proceeds to step S62.

  In step S <b> 62, control device 50 discharges power storage device 30. Control device 50 discharges power storage device 30 with the discharge amount adjusted in step S60. After performing the process of step S62, the control device 50 proceeds to step S64.

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

  In step S <b> 66, the control device 50 generates power from the fuel cell 20. The control device 50 causes the fuel cell 20 to generate power according to the power demand. After performing the process of step S66, the control device 50 ends the control related to the execution process shown in FIG.

  In this way, the charging power with the lowest power unit price is first discharged from the power storage device 30 (see step S62), and the FC power with the next lowest power unit price is generated as necessary (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. Reduction can be achieved. In addition, even if the PV power unit price, purchased power unit price, and FC power generation unit cost vary depending on the season and time, inexpensive power can be preferentially supplied to the load, thus reducing utility costs. Become.

As described above, the power supply system 1 according to the present embodiment can generate power using natural energy, and can also sell the generated power to the commercial power source S (power generation unit). 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 control for controlling charging / discharging of the power storage device 30 Device 50 (control unit), and the control device 50 is a unit price of purchased power that is a unit price of purchased power (a unit price of the purchased power) when the power storage device 30 is charged with the purchased power. , And a charging unit price that is an average unit price of the charged power is calculated based on a selling power unit price when charging the power storage device 30 with the PV power (a selling unit price of the PV power). And the calculated unit charge price And it controls the charging and discharging of the electric storage device 30 based.
By configuring in this way, it is possible to reduce the utility cost according to the fluctuation of the power unit price.

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 that is a time zone in which the power storage device 30 can be charged. Predict the first time zone where surplus of PV power occurs with respect to demand, the second time zone where the purchased power unit price is the minimum, or the third time zone where the purchased power unit price is less than the PV power unit price The predicted first time zone, second time zone, and third time zone are set as the charging timing.
By comprising in this way, the electrical storage apparatus 30 can be charged at the timing when PV surplus electric power is generated, or at the timing when the electric power unit price of the electric power to be charged is low.

The control device 50 can determine a target charge amount that is a charge amount to be charged in the power storage device 30 at each of the charge timings in the planning process, and the first charge that is one of the charge timings. Predict the power demand from the timing to the second charging timing that is the next charging timing of the first charging timing and the power generation amount of the photovoltaic power generation unit 10, based on the predicted power demand and the power generation amount, The target charge amount at the first charge timing is determined.
With this configuration, the power demand until the next charging timing (second charging timing) can be covered by the power discharged from the power storage device 30.

Further, the control device 50, in the planning process, the power selling unit price during charging in the first time zone, the power buying unit price during charging in the second time zone, and the power selling unit price during the third time zone. Priorities are set in order from the lowest unit price with respect to the electricity purchase unit price during charging, and the target charge amount at the charging timing with the highest priority is corrected to the maximum capacity of the power storage device 30.
With this configuration, it is possible to charge a large amount of power with a low power unit price, so that the utility cost can be reduced.

In addition, in the planning process, the control device 50 determines that the priority is second when the maximum capacity is not reached even when charging with the maximum capacity of the power storage device 30 at the charging timing with the highest priority. The shortage is added to the target charge amount at the upper charge timing.
By configuring in this way, even when it is not possible to cover the power demand up to the next charging timing with only the power charged at the charging timing with the lowest power unit price, charging is performed at the charging timing with the second lowest power unit price. Since the generated power can cover the power demand, it can cover the power demand while suppressing the utility cost.

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

In addition, the control apparatus 50 includes the fuel cell 20 capable of generating power using fuel, and the control device 50, 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 Power generation.
By comprising in this way, since the electric power from the fuel cell 20 with a low electric power unit price can be used for an electric power demand, reduction of a utility bill can be aimed at.

Further, the control device 50 discharges the power storage device 30 when the charging 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 power from the power storage device 30 with a low power unit price can be allocated to the power demand, so that the utility cost can be reduced.

Further, the control device 50 is configured such that 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 lower than the current purchased power unit price. In a low case, 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 generates power.
By configuring in this way, it is possible to prevent commercial power from being purchased even though power demand from the power storage device 30 (discharge power) and power from the fuel cell 20 (FC power) can cover power demand. be able to.

In addition, the solar power generation unit 10 according to the present embodiment is an embodiment of the power generation unit.
The control device 50 according to the present embodiment is an embodiment of a control unit.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said structure, A various change is possible within the range of the invention described in the claim.

  For example, in the present embodiment, the power supply system 1 includes the fuel cell 20. However, the power supply system 1 does not necessarily include the fuel cell 20.

  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 takes into account FC power and subtracts the FC power amount from the purchased power amount as a target charge. The amount may be set.

  In the present embodiment, the threshold value α used in the determination in step S54 shown in FIG. 7 is 0.1 kW, but can be an arbitrary value, for example, 0 kW. However, when it is not desired to sell FC power for reasons such as when the power selling unit price is reduced, α is preferably set to a value larger than 0 as in this embodiment.

  In the present embodiment, the threshold value β used in the determination in step S64 shown in FIG. 7 is 0.35 kW, but may be an arbitrary value, for example, 0 kW. However, it is desirable that β be set to a value larger than 0 as in the present embodiment in consideration of a decrease in efficiency caused by operating the fuel cell 20 to cover a small amount of power.

DESCRIPTION OF SYMBOLS 1 Electric power supply system 10 Solar power generation part 20 Fuel cell 30 Power storage device 50 Control apparatus

Claims (9)

A power generation unit capable of generating power using natural energy and selling the generated power to a commercial power source;
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 for controlling charging and discharging of the power storage device;
Comprising
The controller is
Charging unit price when charging the commercial power when the power storage device is charged, and charging unit price when selling the generated power when the power storage device is charged with the generated power. Based on the hourly power unit price, calculate a charging unit price that is an average unit price of the charged power, and control charging and discharging of the power storage device based on the calculated charging unit price.
Power supply system. The controller is
It is possible to execute a planning process for determining a charging timing that is a 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 occurs with respect to the power demand, the second time zone in which the unit purchase price of the commercial power is minimized, or the unit price of the commercial power purchase is the selling price of the generated power. Predicting a third time zone that is less than the unit price of electricity, and predicting the first time zone, the second time zone and the third time zone as the charging timing,
The power supply system according to claim 1. The controller is
In the planning process,
A target charge amount that is a charge amount to be charged to the power storage device at each of the charge timings can be determined,
The power demand from the first charging timing that is one of the charging timings to the second charging timing that is the charging timing next to the first charging timing and the power generation amount of the power generation unit are predicted, and the predicted power demand and Based on the power generation amount, the target charge amount at the first charge timing is determined.
The power supply system according to claim 2. The controller is
In the planning process,
With respect to the unit price of electricity sold during charging in the first time zone, the unit price purchased during charging in the second time zone, and the unit price purchased during charging in the third time zone, the unit prices are in ascending order. Set priorities,
Correcting the target charge amount at the charge timing with the highest priority to the maximum capacity of the power storage device;
The power supply system according to claim 3. The controller is
In the planning process,
If the maximum capacity is not reached even when charging with the maximum capacity of the power storage device at the charging timing with the highest priority, the target charge amount at the charging timing with the second highest priority is insufficient. Add,
The power supply system according to claim 4. The controller is
If the unit price of charging is lower than the current unit price of commercial power, the power storage device is discharged according to power demand.
The power supply system according to any one of claims 1 to 5. A fuel cell capable of generating electricity using fuel,
The controller is
If the unit price of power generation of the fuel cell is lower than the unit price of charge and the unit price of current commercial power purchase, the fuel cell is caused to generate power,
The power supply system according to any one of claims 1 to 6. The controller is
If the unit price of charging is lower than the unit price of power generation of the fuel cell and the current unit price of commercial power, the power storage device is discharged;
The power supply system according to claim 7. The controller is
In the case where the unit price of charging is lower than the unit price of power generation of the fuel cell and the current unit price of power purchase of the commercial power, and the unit price of power generation of the fuel cell is lower than the unit price of power purchase of the current commercial power,
Discharging the power storage device so that the amount of discharge of the power storage device in each time is averaged,
If the averaged discharge amount cannot cover all or part of the predicted power demand, the fuel cell is caused to generate power,
The power supply system according to claim 8.

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