JP7590169B2 - Power demand leveling system and program - Google Patents

Description

The present invention relates to a power demand leveling technology that takes into account the charging and discharging of batteries installed in electric vehicles (EVs) at business establishments, etc.

There is a technology that uses batteries of EVs and the like that are used for commuting but are not used during the daytime peak power demand to level out the power load at low cost. For example, Patent Document 1 discloses a technology that "levels out the power load by releasing the power stored in the batteries during peak power demand at a business, which is an electricity consumer that receives electricity from a power company. The batteries of multiple automobiles are charged at the business during non-peak power demand times or by using the late-night power of each automobile owner, and the power stored in the charged automobile batteries is discharged at the business during peak power demand times for the business (summary excerpt)."

As a specific method, for example, Patent Document 2 discloses a technology in which "based on the operation schedule of a parked electric vehicle, the driver of the electric power consumer inputs the required capacity, which is the battery capacity that the driver wants to reserve, corresponding to multiple times before the start of use of the vehicle, and the licensed capacity for each time, calculated by subtracting the required capacity from the total battery capacity, is output to the electric power supply and demand management center. When controlling the charging and discharging of the battery to level out the supply and demand of electric power, charging and discharging are performed within the licensed capacity for each time based on the charging and discharging command from the electric power supply and demand management center (summary excerpt)."

JP 2007-282383 A International Publication No. 2012/017936

The electricity rate contract (basic rate) of the business operator is a metered system and is determined by the actual peak load of electricity demand. Therefore, reducing the peak load (load leveling; electricity demand leveling) directly leads to a reduction in the business operator's electricity rate contract.

The technology disclosed in Patent Document 1 is a power demand leveling method based on a specific power usage model (specifically, the "valley-peak-valley" model), and assumes that discharge power is prepared in advance or secured by charging during periods of low load. Therefore, it is difficult to apply to power usage that deviates from this model, and has no versatility. In addition, no consideration is given to the mobility needs of EVs (having the necessary remaining battery capacity when you want to use it).

The technology disclosed in Patent Document 2 is a technology that achieves power demand leveling while satisfying mobility needs. However, in order to satisfy mobility needs, the driver specifies in advance for each time period the amount of power to be used for discharging, and discharging is performed within the range of the specified upper limit of power. In other words, the amount of power available for discharging depends on the driver. Therefore, even if an EV has surplus power, it cannot be fully utilized, and there is room for further power demand leveling.

The present invention was made in consideration of the above circumstances, and aims to provide a power demand leveling technology that is highly versatile and can fully and effectively utilize the batteries of electric vehicles.

The present invention provides an electric power demand leveling system that includes a charge/discharge control device that controls charging/discharging of a battery of a connected electric vehicle, and a power management device that controls the power demand of an entire business establishment, and that levels out the power demand of the business establishment, the power management device including a charge/discharge plan creating unit that creates a charge/discharge plan for the battery that reduces a maximum value of a daily power demand of the business establishment based on a remaining capacity when the battery is connected and reservation information for the battery, an instruction unit that issues charge/discharge instructions to the charge/discharge control device in accordance with the charge/discharge plan created by the charge/discharge plan creating unit, and a forecast power demand value for each predetermined time slot of a target day for which the charge/discharge plan is created, as a forecast power demand curve. the battery information acquisition unit acquires the charging completion time of the battery and the charge amount at the completion as the reservation information, and a battery information acquisition unit acquires the specifications of the battery as battery information, and the charge/discharge plan creation unit determines the charge amount and discharge amount for the battery for each of the specified time periods using the connection time when the battery was connected detected by the charge/discharge control device, the predicted power demand curve, the reservation information, and the battery information, and creates the charge/discharge plan according to a predetermined creation procedure in accordance with the shape of the predicted power demand curve for a chargeable/dischargeable period determined by the connection time and the charging completion time .

The present invention provides a highly versatile power demand leveling technology that can fully and effectively utilize the batteries of electric vehicles. Problems, configurations, and effects other than those described above will become clear from the description of the embodiments below.

FIG. 1A is an explanatory diagram for explaining a method for determining a contracted power, and FIGS. 1B and 1C are explanatory diagrams for explaining use cases of an embodiment of the present invention. 1 is an overall configuration diagram of a power leveling system according to an embodiment of the present invention. FIG. 1A is a functional block diagram of a power management apparatus according to an embodiment of the present invention, and FIG. FIG. 1A is an explanatory diagram for explaining the charging state and terminology of an EV battery in an embodiment of the present invention, and FIG. 1B and FIG. 1C are explanatory diagrams for explaining an example of data stored in an EV reservation information database (DB) and an example of data stored in a battery information DB in an embodiment of the present invention, respectively. 3A, 3B, and 3C are explanatory diagrams for explaining an example of data stored in a power usage history DB, a charge/discharge plan DB, and a charge/discharge history DB, respectively, according to an embodiment of the present invention. 5A and 5B are diagrams illustrating a method for calculating an original power usage value and a predicted power demand value according to an embodiment of the present invention. FIG. 1A is an explanatory diagram illustrating an example of a predicted power demand curve according to an embodiment of the present invention, and FIGS. 1B and 1C are explanatory diagrams illustrating an outline of an embodiment of the present invention using specific examples. 1A and 1B are explanatory diagrams for explaining an outline of a charge/discharge plan formulation process according to an embodiment of the present invention. 4 is a flowchart of a charge/discharge plan formulation process according to an embodiment of the present invention. FIG. 2 is an explanatory diagram for explaining an overview of a charging/discharging plan formulation process for each EV battery according to an embodiment of the present invention. 1A to 1H are explanatory diagrams for explaining model patterns according to an embodiment of the present invention. 1A and 1B are explanatory diagrams for explaining the charge/discharge plan development process for model pattern a of an embodiment of the present invention, and FIG. 1C and 1D are explanatory diagrams for explaining the charge/discharge plan development process for model pattern h of an embodiment of the present invention, respectively. 1A is a flowchart of a main process of a charge/discharge plan formulation process in a formulation procedure 1 according to an embodiment of the present invention, and FIG. 1B is a flowchart of a charging plan formulation process in step 1 of the formulation procedure 1 according to an embodiment of the present invention. 1 is a flowchart of a first charging process of a planning procedure 1 according to an embodiment of the present invention. 11 is a flowchart of a second charging process in a planning procedure 1 according to an embodiment of the present invention. 1A and 1B are explanatory diagrams for explaining the charge/discharge plan formulation process for model pattern b of an embodiment of the present invention, and FIG. 1C is an explanatory diagram for explaining the charge/discharge plan formulation process for model pattern h of an embodiment of the present invention, respectively. 1A is a flowchart of a main process of the charge/discharge plan formulation process of the planning procedure 2 according to an embodiment of the present invention, and FIG. 1B is a flowchart of the charge/discharge plan formulation process of procedure 2 of the planning procedure 2 according to an embodiment of the present invention. 13 is a flowchart of a first charging process of a planning procedure 2 according to an embodiment of the present invention. 13 is a flowchart of a second charging process of a planning procedure 2 according to an embodiment of the present invention. 13 is a flowchart of a charge/discharge plan formulation process in step 2 of the formulation procedure 2 according to the embodiment of the present invention. 1A and 1B are explanatory diagrams for explaining the charge/discharge plan formulation process for model pattern d of an embodiment of the present invention, FIG. 1C is an explanatory diagram for explaining the charge/discharge plan formulation process for model pattern g of an embodiment of the present invention, and FIG. 1D and 1E are explanatory diagrams for explaining the charge/discharge plan formulation process for model pattern f of an embodiment of the present invention, respectively. 13A and 13B are flowcharts showing a charge/discharge plan planning process for model pattern d according to an embodiment of the present invention, and FIG. 13C is a flowchart showing a main process of planning procedure 5 according to an embodiment of the present invention. 13 is a flowchart of a first charge/discharge process of a planning procedure 5 according to an embodiment of the present invention. 13A to 13C are flowcharts of a fourth charge/discharge process, a second charge/discharge process, and a third charge/discharge process, respectively, of planning procedure 5 according to an embodiment of the present invention.

The following describes an embodiment of the present invention with reference to the drawings. Note that the present invention is not limited to this embodiment, and all application examples that conform to the concept of the present invention are included in its technical scope. In addition, unless otherwise specified, each component may be multiple or singular.

First, an overview of this embodiment will be described based on a typical use case. In this embodiment, by controlling the charging and discharging of EVs used for commuting or as company cars in a business office or the like, the peak power usage in the business office is reduced and leveled out as much as possible.

Generally, the contracted power is determined based on the actual amount. In other words, the maximum value (maximum demand power amount) of the maximum power demand (power usage) for each month in the past year is set as the contracted power. The maximum demand power amount is the largest value in the month among the average power usage every 30 minutes. For example, it is currently July, and the maximum demand power amount for the past year (July to July) has changed as shown in Figure 1 (a). In this case, it is determined based on the value for September, when the maximum demand power amount was the largest. If the maximum demand power for September can be reduced, the contracted power will also be reduced. Since electricity charges are proportional to the contracted power, reducing the contracted power directly leads to cost reduction.

In this embodiment, the maximum value of the power usage is reduced on a daily basis by using the charging and discharging of the battery (hereinafter referred to as the EV battery) installed in the EV. Specifically, as shown in FIG. 1(b), the power usage in one day changes. In the example of FIG. 1(b), the maximum value is PA [kW]. In this embodiment, the charging and discharging of the EV battery is controlled to reduce the maximum value. As shown in FIG. 1(c), the EV battery is charged during a time period when the maximum value PA is not reached, and the EV is discharged during a time period when power usage is high around the peak time. This reduces the maximum value to PB by discharging, and the maximum power usage for that day can be reduced. By reducing power usage in this way every day, the maximum power demand for that month can be reduced, and the contracted power with the power company can be reduced accordingly, and the purchased power can also be reduced.

Typical use cases are as follows:
1) In the morning, employees come to work and begin charging.
2) When peak load occurs, discharge the EV battery to reduce the peak.
3) After the peak load, if the EV battery remaining capacity (required battery remaining capacity) required by each employee is not reached by the time the employees return home, charging will be performed to ensure the required battery remaining capacity.

The required remaining battery capacity and the charging completion time are specified by employees, etc. Based on that information, the power management device 200, which will be described later, creates a charging and discharging plan to charge the shortfall so that the specified remaining capacity is secured by the specified charging completion time.

In this embodiment, as long as the specified remaining capacity can be secured by the specified charging completion time, the remaining capacity may temporarily become lower than the specified remaining capacity during the process prior to that time. This allows more power to be secured for discharging in a flexible and highly adaptable manner.

[System configuration]
The overall configuration of the power demand leveling system 100 of this embodiment is shown in Fig. 2. As shown in this figure, the power demand leveling system 100 includes a power management device 200, a HUB 110, a power meter 120, an in-house electric system 150, and charge/discharge control devices (PCS: Power Control Systems) 311, 312, 313, and 314 that control the charging and discharging of the batteries (EV batteries) 321, 322, 323, and 324 of the EVs. In the following, unless there is a particular need to distinguish between them, they will be represented by the PCS 310 and the EV battery 320. In addition, the number of the PCS 310 and the EV battery 320 is not limited to this.

The power meter 120 acquires the amount of power supplied from the grid power 130 and outputs it to the power management device 200 via the HUB 110. The amount of power detected by the power meter 120 includes the power used by the in-house electrical system 150 and the power used by the PCS 310.

The power management device 200 creates a charge/discharge plan for each of the EV batteries 320 connected to the power demand leveling system 100, and controls each PCS 310 in accordance with the created charge/discharge plan to charge/discharge the EV batteries 320.

[Functional block of power management device]
Fig. 3(a) shows functional blocks of the power management device 200 of this embodiment. As shown in this figure, the power management device 200 of this embodiment includes an EV reservation information acquisition unit 211, a battery information acquisition unit 212, a power usage acquisition unit 213, a power demand prediction unit 214, a charge/discharge plan creation unit 215, and an instruction unit 216. In addition, the power management device 200 stores, as data, an EV reservation information DB 410, a battery information DB 420, a power usage history DB 430, a charge/discharge plan DB 440, a charge/discharge history DB 450, and a creation procedure DB 460.

The EV reservation information acquisition unit 211 accepts and acquires, from each EV user, the charging completion time and the remaining capacity of the EV battery 320 required at that time (required remaining battery capacity) as EV reservation information. The optimal charging and discharging timing of the EV battery 320 differs for each EV battery 320. Therefore, in this embodiment, EV reservation information is accepted from the user. The EV reservation information is a condition that satisfies mobility needs, for example, a state of charge (SOC) of 90% by 8 p.m.

In this embodiment, the information is received via a UI (an input/output interface, described later) provided in the power management device 200. The received information is stored in the EV reservation information DB 410 in association with information (EVID) that identifies each EV.

Before explaining the EV reservation information DB 410, the SOC of the EV battery 320 and various terms used in this specification will be explained with reference to FIG. 4(a). Here, it is defined as a percentage when the total power Cfull of the EV battery 320 is set to 100%.

The upper limit SOC [%] indicates the maximum amount of power that can be charged (amount of charge) and is the value that becomes the end-of-charge voltage. Charging above this value will result in overcharging. The lower limit SOC [%] indicates the minimum amount of power that can be discharged (amount of charge) and is the value that becomes the end-of-discharge voltage. Discharging below this value will result in overdischarging. In addition, the current SOC [%] is a value that indicates the amount of power (remaining capacity) when connected, and the completion SOC [%] is a value that indicates the amount of power desired by the user at the time charging is completed (the required remaining battery capacity described above).

Further, the amount of energy required for charging Cneed [kWh] is the difference between the amount of energy desired by the user at the time of completion of charging and the current amount of energy (at the time of connection) of the EV battery 320. In this embodiment, it is expressed by the following formula (1) using the total amount of energy Cfull of the EV battery 320.
Cneed=Cfull×{(SOC at completion - current SOC)/100}...(1)

The surplus energy Cexed [kWh] is the difference between the maximum amount of energy that can be charged and the amount of energy desired by the user at the time when charging is completed. In this embodiment, the surplus energy Cexed is expressed by the following formula (2) using the total amount of energy Cfull of the EV battery 320.
Cexed=Cfull×{(upper limit SOC - SOC at completion)/100}...(2)

An example of data (reservation information) stored in the EV reservation information DB 410 is shown in FIG. 4(b). As shown in this figure, the data stored in the EV reservation information DB 410 includes information 411 that identifies the EV battery 320 connected to each PCS 310, connection time 412, charging completion time 413, and completion SOC 414. In addition, the data may include information (PCSID 415) that identifies the connected PCS 310.

The EVID 411 and connection time 412 are stored as values acquired by the PCS 310 to which the EV battery 320 is connected. The EVID 411 is read from the EV battery 320 to which the PCS 310 is connected. The connection time 412 is the time when the PCS 310 detects that the EV battery 320 has been connected. The charging completion time 413 and required remaining battery capacity (SOC at completion 414) are stored as values input by the user. Using this EV reservation information DB 410, the power management device 200 grasps the mobility needs of each EV (there is a required remaining battery capacity when it is desired to use it).

In addition, among the EV reservation information, the charging completion time 413 and the completion SOC 414 input by the user may be configured to hold default values in advance and be changed as necessary for each EV battery 320. The default value may be, for example, 90% by 6 p.m.

The battery information acquisition unit 212 acquires information (battery information) of each EV battery 320. In this embodiment, when the EV battery 320 is connected to the PCS 310, the PCS 310 acquires the battery information from the EV battery 320 and transmits it to the power management device 200 via the HUB 110. At this time, information (PCSID) that identifies the device itself (PCS 310) and information (EVID) that identifies the EV that is equipped with the connected EV battery 320 are also transmitted. The transmitted EV information includes, for example, the capacity (battery capacity) of the EV battery 320, the remaining capacity (current SOC) of the EV battery 320 at the current time, the maximum charge/discharge power (upper limit SOC) of the EV battery 320, and the lower limit receiving power value (lower limit SOC) of the EV battery 320. The battery information acquisition unit 212 acquires the information transmitted from the PCS 310 as battery information and stores it in the battery information DB 420.

An example of data stored in the battery information DB 420 is shown in FIG. 4(c). As shown in this figure, the data includes an EVID 421, a battery capacity 422, a current remaining battery capacity (current SOC 423), a maximum charge amount of the battery (upper limit SOC 424), and a minimum charge amount of the battery (lower limit SOC 425). When the EV battery 320 is connected, the PCS 310 obtains and transmits this information from the connected EV battery 320.

The power usage acquisition unit 213 acquires actual power demand and stores it in a database. In this embodiment, the value of the power meter 120 is acquired as the actual power demand, and for each predetermined time period (time period), the value is stored in the power usage history DB 430 as power usage history in association with the time period.

An example of data stored in the power usage history DB 430 is shown in FIG. 5(a). As shown in this figure, the data stored in the power usage history DB 430 stores the change in power usage 433 for each day in units of a predetermined time period 432 for each date 431. Here, an example is shown in which data is stored in 30-minute units. Furthermore, the power usage history DB 430 further stores, in units of months 434, the maximum power usage, which is the maximum value of the power usage 433 for that month, as a maximum value 435.

The power demand forecasting unit 214 calculates the predicted power demand value for each time period on the planning date when the charge/discharge plan planning unit 215 (described later) plans the plan as a predicted power demand curve. Details of the calculation will be described later.

The charge/discharge plan creation unit 215 creates a charge/discharge plan for each (EV) EV battery 320 connected to each PCS 310. Here, the created charge/discharge plan is the charge/discharge amount for each time period of each EV battery 320. The created charge/discharge plan is stored in the charge/discharge plan DB 440.

As shown in FIG. 5(b), the data stored in the charge/discharge plan DB 440 is created for each planning target date (planning date) 441. Each piece of data includes an EVID 444, which is identification information for the EV battery 320, a PCSID 445, which is identification information for the PCS 310 to which the EV battery 320 is connected, and a planned charge/discharge power amount 443 [kWh] for each predetermined time period 442. That is, the planned charge/discharge power amount 443 [kWh] for each time period 442 is stored for each PCS 310. Note that in this figure, for the planned charge/discharge power amount 443 [kWh], negative values indicate charging and positive values indicate discharging.

In this embodiment, a charge/discharge plan is created according to the mobility needs of each EV, that is, to satisfy the charge completion time 413 specified by the user and the required charge amount at that time (completion SOC 414). In this embodiment, the charge/discharge plan creation unit 215 creates a charge/discharge plan according to the predicted power demand curve and the planning procedure corresponding to the predicted power demand curve stored in the planning procedure DB 460. The plan is created for each EV battery 320 in order according to a predetermined rule. The order of creation is, for example, in order of connection time. If there are multiple EV batteries 320 with the same connection time, the order is in order of the earliest scheduled charge completion time. The charge/discharge plan creation process will be described later.

The instruction unit 216 issues charging and discharging instructions (charge and discharge instructions) to the PCS 310 to which the EV battery 320 is connected, according to the charge and discharge plan for each EV battery 320 created by the charge and discharge plan creation unit 215. Furthermore, in this embodiment, the instruction unit 216 stores the history of the instructions as the charge and discharge history DB 450.

An example of data stored in the charge/discharge history DB 450 is shown in FIG. 5(c). The items of the data stored in the charge/discharge history DB 450 are basically the same as the items of the data stored in the charge/discharge plan DB 440. Specifically, as shown in this figure, each data includes a PCSID 455 and the amount of charge/discharge actually performed (actual charge/discharge power amount 453) for each time period 452 on each date 451. That is, for each PCS 310, the amount of charge/discharge power actually performed for each time period on each planning date is stored.

[Hardware configuration of power management device]
3B is a hardware configuration diagram of the power management apparatus 200 of this embodiment. As shown in this figure, the power management apparatus 200 of this embodiment is configured as a general-purpose information processing device (computer) including a CPU 231, a memory 232, a storage device 233, a communication interface (I/F) 234, and an input/output I/F 235.

Each function of the power management device 200 is realized, for example, by the CPU 231 loading a program stored in the storage device 233 into the memory 232 and executing it. In addition, each piece of data is stored in the storage device 233, etc.

The input/output I/F 235 is, for example, a keyboard, a mouse, a display, a touch panel, etc. In this embodiment, the EV reservation information is input via this input/output I/F 235.

[Power demand forecast processing]
Next, a description will be given of the power demand forecasting process performed by the power demand forecasting unit 214. The power demand forecasting process is a process for forecasting (calculating) a predicted power demand value (predicted power demand curve) for each time period on the planning date (today) from past power usage records.

First, the power demand forecasting unit 214 calculates the original power usage value of the business establishment. The power usage 433 stored in the power usage history DB 430 obtained from the power meter 120 includes the value of the charging/discharging power by the PCS 310. Therefore, from this power usage 433, the actual charging/discharging power amount 453 of each PCS 310 is excluded, and the original power usage (=original power usage) in the case where the charging/discharging power of the PCS 310 is not performed is calculated. Specifically, the calculation is performed according to the following formula (3).
Original power usage = power usage
+ (PCS1 charge/discharge power amount + PCS2 charge/discharge power amount + ...
+ PCSN charge/discharge power amount) ... (3)
It is assumed that N PCSs 310 are provided (N is an integer equal to or greater than 1).
The charge/discharge power amount of each PCS 310 uses the actual charge/discharge power amount 453 at the corresponding date and time of the data stored in the charge/discharge history DB 450. The relationship between the power usage amount 433, the actual charge/discharge power amount 453 which is the usage amount of each PCS 310, and the original power usage value 456 is shown in FIG.

Next, the power demand forecasting unit 214 calculates the predicted power demand value for the business establishment for the predicted time period (prediction time period). For example, the calculation is performed by performing statistical processing on past data for the prediction time period (past original power usage value 461). For example, the maximum and minimum values are excluded from a predetermined number of sampling data, the average value is calculated, and the obtained value is set as the predicted power demand value.

A specific example is shown in FIG. 6(b). Here, an example is shown for the case where the predicted time period is 9:00 in FIG. 6(a). The maximum and minimum values are excluded from the five sampling data points at 9:00 7 days, 14 days, 21 days, 28 days, and 35 days ago, and the average is calculated using the values, and the obtained value is set as the predicted power demand value 457 for this predicted time period (9:00).

Note that, although an example of using past data for the same day of the week has been shown here, the sampling data used is not limited to this. Any data can be selected, such as the same day a year ago, only weekdays of the same month, or past days when the same event was held.

The power demand forecasting unit 214 calculates the predicted power demand value 457 for each time period on the planning day, and obtains a predicted power demand curve as the predicted power demand value for the entire planning day. An example of the obtained predicted power demand curve 510 is shown in FIG. 7(a). Here, each bar graph shows the predicted power demand value 457 for each time period.

The target power amount Ptgt [kWh] is the upper limit of the target power amount for the business establishment. The initial value of the target power amount Ptgt may be a value determined in advance for each business establishment, or may be calculated on a daily basis from past performance. When calculated from past performance, the lower limit may be set to, for example, 30% of the upper limit of the past performance peak.

[Overall charge/discharge plan planning process]
Next, a description will be given of a charging/discharging plan creation process performed by the charging/discharging plan creation unit 215 of this embodiment. An optimal charging/discharging plan that minimizes peaks in power demand is created based on the predicted power demand curve 510 and mobility needs.

The charge/discharge plan creation unit 215 creates a charge/discharge plan for each connected EV battery 320 using the predicted power demand curve 510 for the planning date calculated by the power demand prediction unit 214. In this embodiment, the charge/discharge plan creation unit 215 creates a charge/discharge plan for each connected EV battery 320 in a predetermined order and updates the predicted power demand curve 510. The charge/discharge plan is created to minimize the maximum daily power demand of the business while satisfying mobility needs (remaining battery capacity required when needed).

First, an overview will be given using a specific example. Here, explanation will be given using the predicted power demand curve 510 shown in FIG. 7(a). Also, assume that two EV batteries 321, 322 are connected. As shown in FIG. 7(b), EV battery 321 is connected at 8:00, and 20:00 is specified as the charging completion time in the EV reservation information, and as shown in FIG. 7(c), EV battery 322 is connected at 6:00, and 9:00 is specified as the charging completion time. Hereinafter, the time when the EV battery is connected is represented by Ts, and the charging completion time specified by the user is represented by Te.

In such a case, the optimal charge/discharge plan for EV battery 321 would be to charge in time periods A and C, and discharge in time period B, as shown in FIG. 7(b). The optimal charge/discharge plan for EV battery 322 would be to charge in area A, and not discharge, as shown in FIG. 7(c). In this way, the optimal charge/discharge plan differs depending on the needs of the EV battery.

The charge/discharge plan creation unit 215 first creates a charge/discharge plan for the EV battery 322. FIG. 8(a) shows the charge amount 512 according to the charge/discharge plan for the EV battery 322. Once the charge amount 512 for the EV battery 322 has been determined, the power demand value for each time period, including the charge amount 512, is set as a predicted power demand curve 510, and the charge/discharge plan creation unit 215 creates a charge/discharge plan for the EV battery 321. FIG. 8(b) shows the predicted power demand curve 510 obtained as a result, which includes the charge amount and discharge amount 513 according to the charge/discharge plan for the EV battery 321.

In this manner, in this embodiment, an optimal charge/discharge plan is created for each EV battery 320 in a predetermined order. A charge/discharge plan is created for the first EV battery, and the result is reflected in the predicted power demand value for each time period (the charge amount is added and the discharge amount is subtracted). When planning the next second EV battery, an optimal charge/discharge plan is created for the predicted power demand value for each time period in which the plan for the first EV battery is reflected. This is repeated for each connected EV battery 320, and as a result, an optimal charge/discharge plan is created overall.

When multiple EV batteries 320 are connected, a rule is determined in advance for the order in which the charging and discharging plans are created. The rule is, for example, to give priority to an EV battery 320 with a shorter period between the EV connection time and the EV reservation charging completion time and an earlier EV reservation charging completion time, or to give priority to an EV battery with an earlier EV reservation charging completion time, etc.

The charging and discharging plan for the EV battery 320 is created when the EV battery 320 is connected, and is updated at regular intervals (e.g., once every 30 minutes) until the EV scheduled charging is completed or the EV battery 320 is disconnected.

The above process is shown in the form of a process flow. FIG. 9 shows the process flow of the charge/discharge plan creation process by the charge/discharge plan creation unit 215 of this embodiment. As described above, this process is performed at a predetermined time interval (e.g., every 30 minutes, etc.).

The charge/discharge plan creation unit 215 acquires an initial predicted power demand curve and a target power amount Ptgt (step S1101). As the initial predicted power demand curve, the predicted power demand curve 510 for the planning date calculated by the power demand prediction unit 214 is used. In addition, a preset value is used as the target power amount Ptgt.

First, the charge/discharge plan creation unit 215 determines whether there is an EV battery 320 for which a charge/discharge plan has not been created (hereinafter simply referred to as an unplanned EV) (step S1102). Here, it determines whether there is an EV battery 320 that is connected to the PCS 310 and for which a charge/discharge plan has not been created at the time this process is performed. If there is no unplanned EV, the process ends.

On the other hand, if there are unplanned EVs, the charge/discharge plan creation unit 215 extracts from among them the EV battery (target EV) for which a charge/discharge plan is to be created (step S1103). The extraction is performed according to a predetermined rule. The rule may be, for example, to give priority to the EV battery 320 with the earliest connection time, or, among EV batteries 320 with the same connection time, to the EV battery with the earliest charging completion time. Also, if there is only one unplanned EV, the unplanned EV is set as the target EV.

Next, the charge/discharge plan creation unit 215 creates a charge/discharge plan for the target EV (step S1104). Specifically, it determines the charge and discharge amounts for each time period. The details of the determination will be described later.

Then, the charge/discharge plan creation unit 215 adds the charge/discharge plan of the target EV to the predicted power demand curve at that time, and updates the predicted power demand curve (step S1105). Adding the charge/discharge plan means adding the change in the power demand value due to the charge/discharge plan. Then, the target EV is removed from the unplanned EVs (step S1107), and the process returns to step S1102 and is repeated.

[Individual charge/discharge plan planning process]
The charge/discharge plan creation process (the process of step S1104) for each EV battery 320 by the charge/discharge plan creation unit 215 will be described in detail below. In this embodiment, a charge/discharge plan is created according to a planning procedure stored in advance in the planning procedure DB 460 in accordance with the shape of the predicted power demand curve 510 from the EV connection time Ts to the charging completion time Te. The planning procedure DB 460 stores the planning procedure in accordance with the shape of the predicted power demand curve 510.

Specifically, in this embodiment, as shown in FIG. 10, the predicted power demand curve 510 is divided into three equal parts for the period Td between the EV connection time Ts and the charging completion time Te (chargeable/dischargeable period), and an identifier is assigned to each period X, Y, and Z. The assigned identifier is either CC, which means that the period is mainly for charging, or DD, which means that the period is mainly for discharging, in relation to the predicted power demand value for that period and the target power amount Ptgt. Then, a model pattern is determined by the arrangement of the identifiers, and a planning procedure corresponding to the determined model pattern is stored in the planning procedure DB 460.

If there is even one time period in each of the periods X, Y, and Z in which the magnitude of the predicted power demand value is greater than the target power amount Ptgt, the identifier DD is assigned to that period. The identifier CC is assigned to other periods, i.e., periods in which there is no time period in which the predicted power demand value is greater than the target power amount Ptgt.

There are eight model patterns, depending on the combination, as follows. Figures 11(a) to 11(h) show the relationship between the forecasted power demand curve 510 and the target power amount Ptgt for each model pattern.

The forecasted power demand curve 510a for model pattern a is shown in FIG. 11(a). In model pattern a, the periods (X, Y, Z) are assigned identifiers (CC, CC, CC), respectively.

The forecasted power demand curve 510b for model pattern b is shown in Figure 11 (b). In model pattern b, the periods (X, Y, Z) are assigned identifiers (CC, CC, DD), respectively.

The forecasted power demand curve 510c for model pattern c is shown in Figure 11 (c). In model pattern c, the periods (X, Y, Z) are assigned identifiers (CC, DD, CC), respectively.

The forecasted power demand curve 510d for model pattern d is shown in FIG. 11(d). In model pattern d, the periods (X, Y, Z) are assigned identifiers (DD, CC, CC), respectively.

The forecasted power demand curve 510e for model pattern e is shown in FIG. 11(e). In model pattern e, the periods (X, Y, Z) are assigned identifiers (CC, DD, DD), respectively.

The forecasted power demand curve 510f for model pattern f is shown in FIG. 11(f). In model pattern f, the periods (X, Y, Z) are assigned identifiers (DD, CC, DD), respectively.

The forecasted power demand curve 510g for model pattern g is shown in FIG. 11(g). In model pattern g, the periods (X, Y, Z) are assigned identifiers (DD, DD, CC), respectively.

The forecasted power demand curve 510h for model pattern h is shown in FIG. 11(h). In model pattern h, the periods (X, Y, Z) are assigned identifiers (DD, DD, DD), respectively.

Below, we explain the planning procedures stored in the planning procedure DB460 in association with each model pattern.

First, we will explain the planning procedure (planning procedure 1) associated with model pattern a and model pattern h. As shown in Figures 12(a) and 12(c), in these model patterns, the predicted power demand curve 510a is greater than the target power amount Ptgt and the predicted power demand curve 510h is less than the target power amount Ptgt in all periods. Therefore, the same identifier, either CC or DD, is assigned to all periods X, Y, and Z.

In the planning procedure 1 applied to these model patterns, only a charging plan is created. In other words, a discharging plan is not necessary. Note that since the predicted power demand curve 510 is smaller than the target power amount Ptgt, an identifier DD is assigned to indicate a discharging area for classification purposes. However, since mobility needs are given priority, discharging is not performed and only charging is performed. Below, planning procedure 1 is explained as the flow of processing executed by the charge/discharge plan creation unit 215.

First, the process flow of the main process is shown in FIG. 13(a). As shown in this figure, the charge/discharge plan creation unit 215 performs step 1 of creating a charging plan (step S1201), and ends the process.

Next, the flow of the charging plan creation process of step 1 in step S1201 by the charging/discharging plan creation unit 215 is shown in FIG. 13(b). It will also be described with reference to FIG. 12(b) and FIG. 12(d).

First, the charge/discharge plan creation unit 215 sets the maximum power demand value Pmax_0 during the period Td from Ts to Te in the figure to Pmax_1, as shown in Figures 12(b) and 12(d) (step S1301).

Then, the charge/discharge plan creation unit 215 first performs a first charging process (step S1302). Here, the first charging process is a process that is performed during a time period when the power demand value is equal to or less than Pmax_1. Details of the process will be described later.

Next, the charge/discharge plan creation unit 215 determines whether the total charge amount (total charge amount) Ctotal created in the first charging process has reached the required charging power amount Cneed shown in FIG. 4(a), i.e., whether charging has been completed for Cneed (step S1303). If completed, the charging plan creation process is terminated.

On the other hand, if the charging is not completed, the charge/discharge plan creation unit 215 performs a second charging process (step S1304) and ends the process. Here, the second charging process is a process that is performed for a time period when the power demand value is greater than Pmax_1. Details of the process will be described later.

Next, the flow of the first charging process by the charge/discharge plan creation unit 215 will be described with reference to FIG. 14. In the first charging process, as shown by circled numbers 1 and 2 in FIG. 12(b) and FIG. 12(d), the maximum chargeable amount is assigned as the charging amount to each time slot, starting from the earliest time slot, until the required charging energy amount Cneed is reached.

First, the charge/discharge plan creation unit 215 identifies the number of time periods within the Td period (step S1401). Here, it is assumed that there are M time periods. Then, the processing order is determined for all time periods within the Td period. In the creation procedure 1, it is determined that processing will be performed in order from the earliest time period to the latest time period. For example, each time period is assigned a consecutive number and processed in that order. Furthermore, the charge/discharge plan creation unit 215 calculates the available capacity Stn, which is the difference between the power demand value Ptn and Pmax_1, for each time period tn (n is an integer between 1 and M).

The charge/discharge plan creation unit 215 first sets the counter n to 1 (step S1402). At this time, the total charge amount Ctotal is set to 0.

The charge/discharge plan creation unit 215 determines whether the total charge amount Ctotal has reached the required charge power amount Cneed (step S1403), and if so, ends the process.

If not reached, the charge/discharge plan creation unit 215 determines whether the available capacity Stn is greater than the maximum chargeable capacity PCSmax (Stn>PCSmax) (step S1404). Here, the maximum chargeable capacity PCSmax is the maximum amount of chargeable power in a time period (here, 30 minutes) of the PCS310 to which the target EV (EV battery 320) is connected.

If Stn>PCSmax, the maximum chargeable amount PCSmax is set as the charge amount Ctn for the time period tn (step S1405). Then, the power demand value Ptn for the time period tn is updated to a value obtained by adding PCSmax, and the total charge amount Ctotal is updated to a value obtained by adding PCSmax (step S1406). Note that the time period tn in which the charge amount Ctn is set to the maximum chargeable amount PCSmax is excluded from the processing target of the second charging process described below (step S1409).

On the other hand, if Stn≦PCSmax, the charge amount Ctn for the time period tn is set to the available capacity Stn (step S1407). Then, the power demand value Ptn for the time period tn is updated to a value obtained by adding the charge amount Ctn, and the total charge amount Ctotal is updated to a value obtained by adding the charge amount Ctn (step S1408).

After updating the power demand value Ptn and the total charge amount Ctotal for the time period tn, it is determined whether processing has been completed for all periods (steps S1409 and S1410). Here, the counter n is incremented by 1, and it is determined whether M has been exceeded. If it has not been exceeded, the process returns to step S1403 and continues processing.

On the other hand, if processing has been completed for all periods, the process ends.

Next, the flow of the second charging process by the charge/discharge plan creation unit 215 will be described with reference to FIG. 15. This process is performed when the required amount of charging cannot be achieved by the first charging process alone. This process is performed when the required charging cannot be achieved within the range of the target power amount Ptgt (or the maximum value Pmax_1). Therefore, as shown by the circled number 3 in FIG. 12(b) and FIG. 12(d), the maximum power demand value for the period Td is increased. In these figures, it is increased from Pmax_1 to Pmax_2. Note that in this embodiment, the time slots tn that were excluded from the processing target in the first charging process are not included. In other words, only the time slots tn that are not excluded are included.

As shown in FIG. 15, the charge/discharge plan creation unit 215 first acquires and calculates various information necessary for the second charging process (step S1501). Here, the information is the total charge amount Ctotal calculated in the first charging process, the target time periods tn of the second charging process, the number M2 of the time periods, and the available charge capacity Stn2 in each target time period tn. The available capacity Stn2 is the difference between the maximum chargeable capacity PCSmax determined by the PCS310 and the charge amount Ctn determined in the first charging process.

After calculating each of these pieces of information, the charge/discharge plan creation unit 215 determines the processing order of the time slot tn to be processed and performs the following processing (step S1502). For example, the processing order is such that the time slot tn having the smallest free space Stn2 value and the earliest time slot is given priority. n is a counter.

The charge/discharge plan creation unit 215 determines whether the total charge amount Ctotal has reached the required charge power amount Cneed (step S1503), and if so, ends the process.

If the target has not been reached, the charge/discharge plan creation unit 215 adds the free capacity Stn2 to the charge amount Ctn for the time period tn (step S1504). That is, the charge amount Ctn for the time period tn is updated to a value obtained by adding the free capacity Stn2. Then, the power demand value Ptn for the time period tn is updated to a value obtained by adding the free capacity Stn2, and the total charge amount Ctotal is updated to a value obtained by adding the free capacity Stn2 (step S1505). In addition, as shown in Figures 12(b) and 12(d), the obtained power demand value Ptn is set as the maximum power demand value Pmax_2 for the period Td (step S1506).

Then, it is determined whether processing has been performed for all time periods tn that are the target of the second charging process (steps S1507 and S1508). If processing has been performed, the processing ends. If processing has not been performed, the process returns to step S1503 and processing for the next time period is performed.

The above charge and discharge plan determines the charge amount Ctn and power demand value Ptn for the target EV for each time slot tn in the period Td. That is, the planned charge and discharge power amount 443 of the EV battery 320 for each time slot shown in FIG. 5(b) above is determined. In addition, the maximum power demand value Pmax_2 for the period Td after taking into account the charge and discharge plan is also determined.

Next, we will explain planning procedure 2, which is stored in the planning procedure DB 460 in association with model patterns b and e. As shown in Figures 16(a) and 16(c), in these model patterns, the predicted power demand curves 510b and 510e increase almost monotonically and exceed the target power amount Ptgt within the period Td. In other words, the CC identifier is assigned to the early time period, and the DD identifier is assigned to the later time period. In such a model pattern, the area where the predicted power demand value is less than the target power amount Ptgt is the chargeable area, and the area where the predicted power demand value is equal to or greater than the target power amount Ptgt is the dischargeable area.

In planning procedure 2 applied to these model patterns, first, a charging plan is created for a time period in which the predicted power demand value is smaller than the target power amount Ptgt, and then a discharging plan is created including the power amount added in the charging plan. That is, the processing is performed in the order shown by the circled numbers in FIG. 16(b). Here, circled numbers 1 to 3 indicate the processing for determining the charging amount, and circled numbers 4 indicates the processing for determining the discharging amount. This makes it possible to reduce the maximum power demand value for the period Td, which was initially Pmax_1, to Pmax_3.

This planning procedure 2 will be explained using Figures 17(a) to 20 as the flow of processing executed by the charge/discharge plan planning unit 215.

First, the process flow of the main process is shown in FIG. 17(a). As shown in this figure, the charge/discharge plan creation unit 215 performs a procedure 2 charge plan creation process to create a charge plan (step S2201). After that, it performs a procedure 2 discharge plan creation process to create a discharge plan (step S2202), and ends the process.

Next, the flow of the step 2 charging plan planning process of planning procedure 2 is basically the same as the step 1 charging plan planning process of planning procedure 1. However, as shown in FIG. 17(b), here, the charge/discharge plan planning unit 215 sets the target power amount Ptgt to Pmax_1 (step S2301). Also, the target charging amount includes not only the charging required power amount Cneed but also the surplus power amount Cexed shown in FIG. 4(a). That is, as in planning procedure 1, the first charging process is performed (step S2302), and then it is determined whether the planned total charging amount Ctotal has reached the sum of the charging required power amount Cneed and the surplus power amount Cexed (step S2303), and if not, the second charging process, etc. is performed (step S2304).

Next, the first charging process of planning procedure 2 will be described with reference to FIG. 18. The first charging process of planning procedure 2 is basically the same as the first charging process of planning procedure 1. However, the time period tn to be processed is a time period in which the power demand value Ptn is smaller than the target power amount Ptgt (= Pmax_1). In addition, with regard to the processing order, the largest value of the free capacity Stn is given top priority, and the time is given the next priority.

First, the charge/discharge plan creation unit 215 identifies the number of time periods to be processed within the Td period (step S2401). Here, as described above, the time periods tn to be processed are time periods in which the power demand value Ptn is smaller than the target power amount Ptgt (= Pmax_1), so the number of such time periods is identified (assuming M). Then, for the time periods tn, the available capacity Stn, which is the difference between the power demand value Ptn and Pmax_1, is calculated. Also, as described above, the processing order is determined so that the processing is performed in descending order of the available capacity Stn, and within that, in descending order of time.

The counter n is set to 1 and the total charge amount Ctotal is set to 0 (step S2402), and then the charge/discharge plan creation unit 215 performs the following processing for the M processing time periods tn that have been determined.

The charge/discharge plan creation unit 215 determines whether the total charge amount Ctotal reaches the sum of the charge required energy amount Cneed and the surplus energy amount Cexed (step S2403), and if so, ends the processing.

If not reached, the charge/discharge plan creation unit 215 determines whether the available capacity Stn is greater than the maximum chargeable capacity PCSmax (Stn>PCSmax) (step S2404).

If Stn>PCSmax, the maximum chargeable amount PCSmax is set as the charge amount for time period tn (step S2405). Then, the power demand value Ptn for that time period tn is updated to a value obtained by adding PCSmax, and the total charge amount Ctotal is updated to a value obtained by adding PCSmax (step S2406). Note that the time period tn in which the charge amount is the maximum chargeable amount PCSmax is excluded from the processing target of the second charging process described below (step S2409). The time period tn that is the target of this processing is indicated by the circled number 1 in FIG. 16(b).

On the other hand, if Stn≦PCSmax, the charge amount Ctn for the time period tn is set to the available capacity Stn (step S2407). Then, the power demand value Ptn for the time period tn is updated to a value obtained by adding the charge amount Ctn, and the total charge amount Ctotal is updated to a value obtained by adding the charge amount Ctn (step S2408). The time period tn that is the subject of this process is indicated by the circled number 2 in FIG. 16(b).

After updating the power demand value Ptn and the total charge amount for time period tn, it is determined whether processing has been completed for all periods (steps S2409 and S2410). Here, the counter n is incremented by 1, and it is determined whether M has been exceeded. If it has not been exceeded, the process returns to step S2403 and continues processing.

On the other hand, if processing has been completed for all periods, the process ends.

Next, the flow of the second charging process by the charge/discharge plan planning unit 215 in the case of planning procedure 2 will be described with reference to FIG. 19. As with planning procedure 1, this process is performed when the required amount of charging cannot be achieved by the first charging process alone. Only the time period tn that was not excluded in the first charging process is targeted. The process flow is basically the same as the flow of the second charging process in planning procedure 1. The time period tn targeted by this process is indicated by the circled number 3 in FIG. 16(b).

First, various information required for the second charging process is acquired and calculated (step S2501). Here, the information is the total charge amount Ctotal calculated in the first charging process, the target time periods tn of the second charging process, the number M2 of the time periods, and the free space Stn2 of each target time period tn. The free space Stn2 is the difference between the maximum chargeable amount PCSmax and the charge amount Ctn determined in the first charging process.

After calculating each of these pieces of information, the charge/discharge plan creation unit 215 determines the processing order of the time slot tn to be processed and performs the following processing (step S2502). For example, the processing order is such that the time slot tn having the smallest free space Stn2 value and the earliest time slot is given priority. n is a counter.

The charge/discharge plan creation unit 215 determines whether the total charge amount Ctotal reaches the sum of the charge required energy amount Cneed and the surplus energy amount Cexed (step S2503), and if so, ends the processing.

If the target has not been reached, the charge/discharge plan creation unit 215 adds the free capacity Stn2 to the charge amount Ctn for the time period tn (step S2504). Then, the power demand value Ptn for the time period tn is updated to a value that includes the free capacity Stn2, and the total charge amount Ctotal is updated to a value that includes the free capacity Stn2 (step S2505). In addition, as shown in FIG. 16(b), the obtained power demand value Ptn is set as the maximum power demand value Pmax_2 for the period Td (step S2506).

Then, it is determined whether processing has been performed for all time periods tn that are the target of the second charging process (steps S2507 and S2508). If processing has been performed, the processing ends. If processing has not been performed, the process returns to step S2503 and processing for the next time period is performed.

Note that in planning procedure 2, since a discharge process is also performed, the surplus power amount Cexed is also allocated to charging in the second charging process. However, the surplus power amount Cexed does not have to be allocated to charging. In other words, if Ctotal reaches Cneed in step S2503 above, the process may end.

Next, the flow of the procedure 2 discharge plan creation process by the charge/discharge plan creation unit 215 in the case of creation procedure 2 will be described with reference to FIG. 20. The discharge plan is assigned only when there is surplus power Cexed. The time period tn targeted by this process is indicated by the circled number 4 in FIG. 16(b).

First, the charge/discharge plan creation unit 215 sets the maximum power demand value Pmax_0 within the period Td to Pmax_1 (step S2601).

First, the time periods tn in which the initial power demand value Ptn is large are extracted from the target power amount Ptgt (step S2602). The number of such periods is then identified. Here, this is set to M3. The processing order is then determined so that processing is performed in descending order of power demand value Ptn. If there are multiple time periods with the same power demand value, the processing order is determined so that processing is performed in ascending order of time. The following processing is performed according to the determined processing order (step S2603).

First, the charge/discharge plan creation unit 215 determines whether or not there is any surplus power Cexed remaining (step S2604). If there is no surplus power remaining, the process ends.

The difference ΔPtn1 between the power demand value Ptn of the time period tn in which the power demand value is the highest and the power demand value of the time period in which the power demand value is the second highest is calculated, and this is set as the discharge amount Dtn of the time period tn in which the power demand value Ptn is the highest (step S2605).

Then, the power demand value Ptn for the time period tn is updated to a value excluding Dtn, and the surplus power amount Cexed is updated to a value excluding the discharge amount Dtn (step S2606). As shown in FIG. 16(b), the obtained power demand value Ptn is set as the maximum power demand value Pmax_3 for the period Td (step S2607). Note that, for example, if there are multiple time periods with the highest power demand value, when processing of all of these time periods is completed, the power demand value Ptn is set as the maximum power demand value Pmax_3 for the period Td.

Then, it is determined whether processing has been completed for all M3 time slots (steps S2608, S2609). If processing has been completed, the surplus power amount Cexed is left and processing ends. On the other hand, if there are unprocessed time slots tn, the process returns to step S2604 and processing is performed for the next time slot determined in the processing order.

Planning procedure 3 associated with model pattern d and model pattern g, and planning procedure 4 associated with model pattern f are basically the same as planning procedure 2. However, when determining the processing order of the first charging process, planning procedure 2 prioritizes the earlier one, whereas planning procedure 3 prioritizes the later one. In the case of planning procedure 4, either is acceptable.

As shown in Figures 21(a) and 21(c), in model patterns d and g, the predicted power demand curves 510d, 510g decrease almost monotonically and become smaller than the target power amount Ptgt within period Td. That is, the early time period is assigned the DD identifier, and the later time period is assigned the CC identifier. In such model patterns, the area of the predicted power demand value equal to or greater than the target power amount Ptgt is the dischargeable area, and the area below the target power amount Ptgt is the chargeable area.

In planning procedure 3 applied to these model patterns, first, a charging plan is created for a time period in which the predicted power demand value is smaller than the target power amount Ptgt, and then a discharging plan is created including the power amount added in the charging plan. That is, the processing is performed in the order shown by the circled numbers in FIG. 21(b). Here, circled numbers 1 to 3 indicate the processing for determining the charging amount, and circled numbers 4 is the processing for determining the discharging amount. This makes it possible to reduce the maximum power demand value for the period Td, which was initially Pmax_1, to Pmax_3.

In addition, in model pattern f, the predicted power demand curve 510f changes from decreasing to increasing within the period Td. As shown in FIG. 21(d), in this model pattern f, as in the other model patterns, the area where the predicted power demand value is equal to or greater than the target power amount Ptgt is the dischargeable area, and the area where the predicted power demand value is less than the target power amount Ptgt is the chargeable area.

In planning procedure 4 applied to this model pattern f, first, a charging plan is created for a time period in which the predicted power demand value is smaller than the target power amount Ptgt, and then a discharging plan is created including the power amount added in the charging plan. That is, the processing is performed in the order shown by the circled numbers in FIG. 21(e). Here, circled numbers 1 to 3 indicate the processing for determining the charging amount, and circled numbers 4 is the processing for determining the discharging amount. This makes it possible to reduce the maximum power demand value for the period Td, which was initially Pmax_1, to Pmax_3.

Next, we will explain the planning procedure 5 associated with model pattern c. As shown in FIG. 22(a), in this model pattern c, the predicted power demand curve 510c changes from increasing to decreasing during the period Td, with the minimum value being smaller than the target power amount Ptgt and the maximum value being larger than the target power amount Ptgt. As shown in this figure, in model pattern c, as in the other model patterns, the area where the predicted power demand value is less than the target power amount Ptgt is the chargeable area, and the area where the predicted power demand value is equal to or greater than the target power amount Ptgt is the dischargeable area.

In the planning procedure 5 applied to the model pattern c, first, a charging plan is created for a later time period (circled numbers 1 and 2 in FIG. 22(b)), then a charging plan is created for an earlier time period (circled numbers 3 and 4 in FIG. 22(b)), and finally a discharging plan for the dischargeable region is created (circled number 5 in FIG. 22(b)). This makes it possible to reduce the maximum power demand value for the period Td, which was initially Pmax_1, to Pmax_3. Below, the planning procedure 5 is explained as the flow of the process executed by the charge and discharge plan creation unit 215.

First, the flow of the main processing of planning procedure 5 by the charge/discharge plan planning unit 215 is shown in Figure 22 (c).

First, the charge/discharge plan creation unit 215 performs period Z charging processing to create a charging plan for period Z (step S5101).

Then, the charge/discharge plan creation unit 215 determines whether the created total charge amount Ctotal reaches the sum of the required charge energy amount Cneed and the surplus energy amount Cexed (step S5102), and if so, performs the first charge/discharge process (step S5103) and ends the process.

On the other hand, if the required charging amount Cneed has not been reached, the charge/discharge plan creation unit 215 determines whether the planned total charging amount Ctotal has reached the required charging amount Cneed (step S5104), and if so, performs a second charge/discharge process (step S5105) and ends the process.

On the other hand, if the target has not been reached, the charge/discharge plan creation unit 215 performs a third charge/discharge process (step S5106) and ends the process.

Explains period Z charging processing.

The period Z charging process is basically the same as the first charging process in planning procedure 2. However, the order of processing is such that the later one takes precedence. The other processes are the same as the first charging process, so a description will be omitted here.

Next, the first charging/discharging process of step S5103 will be described. Figure 23 shows the processing flow of the first charging/discharging process.

The charge/discharge plan creation unit 215 sets the maximum power demand value in the period Y to Pmax_1 (step S5201). Period Y is the only region among the three regions that has a time period that is equal to or greater than the target power amount Ptgt. Therefore, this is equivalent to setting the maximum power demand value (Pmax_0) in the period Td to Pmax_1.

Next, among the time periods in period Y, the time periods in which the power demand value is greater than the target power amount Ptgt are set as discharge target periods, the number of such time periods is identified, and the processing order is determined (step S5202). The number is set to M3. The processing order is determined so that processing is performed in descending order of the power demand value Ptn. If there are multiple time periods with the same power demand value, the processing order is determined so that processing is performed in ascending order of time. The following processing is performed according to the determined processing order (step S5203).

First, the charge/discharge plan creation unit 215 determines whether the difference ΔSOC1 between the current SOC and the lower limit SOC is equal to or greater than the surplus power amount Cexed (step S5204). The current SOC and the lower limit SOC are each obtained from the battery information DB 420.

If the difference ΔSOC1 is equal to or greater than the surplus power amount Cexed, a discharge plan is created with the smaller surplus power amount Cexed as the upper limit. The flow of the discharge plan creation process is basically the same as the discharge plan creation process in the creation procedure 2.

That is, first, it is determined whether surplus power Cexed remains (step S5205). If so, according to the processing order determined in step S5202, the difference ΔPtn1 between the power demand value Ptn of the time slot tn with the highest power demand value and the power demand value of the time slot with the second highest power demand value is calculated, and this is set as the discharge amount Dtn of the time slot tn with the highest power demand value Ptn (step S5206).

Then, the power demand value Ptn for the time period tn is updated to a value excluding Dtn, and the surplus power amount Cexed is updated to a value excluding the discharge amount Dtn (step S5207). The maximum power demand value Ptn at that time point is set as the maximum power demand value Pmax_3 for the period Y (step S5208).

Then, it is determined whether processing has been completed for all M3 time periods (steps S5209 and S5210). If not, the process returns to step S5205.

On the other hand, if processing has been completed for all target discharge time periods, in the case of planning procedure 5, the process proceeds to S5221 described below. Also, if there is no surplus power Cexed remaining in step S5205, the process proceeds to S5221.

In addition, in step S5204, if the difference ΔSOC1 is less than the surplus power amount Cexed, a discharge plan is created with the smaller difference ΔSOC1 as the upper limit. The flow of the discharge plan creation process is basically the same as the discharge plan creation process in the creation procedure 2 and the above-mentioned case where the surplus power amount Cexed is used as the upper limit.

That is, while the difference ΔSOC1 remains, or until processing is completed for all M3 time periods tn (steps S5215, S5219, S5220), the discharge amount Dtn for tn is determined (step S5216), the power demand value Ptn is updated to a value excluding Dtn, and the difference ΔSOC1 is updated to a value excluding the discharge amount Dtn (step S5217), and the maximum power demand value Ptn at that time point is set as the maximum power demand value Pmax_3 for period Y (step S5218).

Then, the charge/discharge plan creation unit 215 determines whether there is an unprocessed discharge target time period (step S5221), and if there is an unprocessed time period, performs the fourth charge/discharge process (step S5222) and ends the process. Note that an unprocessed time period exists when the surplus power amount Cexed or the difference ΔSOC1 has disappeared and the process proceeds to step S5221.

Here, the flow of this fourth charge/discharge process will be explained using Figure 24 (a). This fourth charge/discharge process creates a charging plan using the time period of period X and the time period in which the power demand value is smaller than the target power amount Ptgt for period Y, with the smaller of the dischargeable power amount PD for the unprocessed target discharge time period and the difference ΔSOC2 between the upper limit SOC and the current SOC as the upper limit. Then, the amount of charge is added to determine the discharge amount for the unprocessed target discharge time period.

As shown in this figure, the charge/discharge plan creation unit 215 calculates the amount of dischargeable power PD and determines whether the amount of power PD is greater than the difference ΔSOC2 (step S5301). If the amount of power PD is greater, a charging plan is created with the smaller difference ΔSOC2 as the upper limit (step S5302). Otherwise, a charging plan is created with the amount of power PD as the upper limit (step S5303).

At this time, the time periods for which the charging plan is created are the time periods included in period X and the time periods other than the discharge target time periods in period Y. The creation of the charging plan is basically the same as the first charging process described above. However, whereas in the first charging process, the upper limit is the amount of energy required for charging Cneed, here it is the difference ΔSOC2 or the amount of energy PD, respectively.

Next, a discharge plan is created for the unprocessed time period with the charge amount secured in step S5302 or step S5303 as the upper limit (step S5304), and the process ends.

This discharge plan is basically the same as the discharge plan formulation process in the above-mentioned formulation procedure 2. However, whereas in the discharge plan formulation process in formulation procedure 2, the upper limit is set to the surplus power amount Cexed, here, the upper limit is set to the charge amount secured in step S5302 or step S5303.

Next, the second charging/discharging process of step S5105 will be described. FIG. 24(b) shows the processing flow of the second charging/discharging process.

As in the first charging/discharging process, the charging/discharging plan creation unit 215 sets the maximum power demand value (=Pmax_0) during period Y to Pmax_1 (step S5401).

Then, similar to the first charging/discharging process, among the time periods in period Y, the time periods in which the power demand value is greater than the target power amount Ptgt are set as the discharging target period, and the fourth charging/discharging process is executed (step S5402).

Next, the third charging/discharging process of step S5106 will be described. Figure 24 (c) shows the processing flow of the third charging/discharging process.

As in the first charging/discharging process, the charging/discharging plan creation unit 215 sets the maximum power demand value during period Y to Pmax_1 (step S5501).

The charge/discharge plan creation unit 215 creates a charging plan with the sum of the charging required energy Cneed and the surplus energy Cexed as the upper limit (step S5502). Here, the time period for which the charging plan is created is the time period included in period X and the time period other than the discharge target time period in period Y. The charging plan is created basically in the same manner as the first charging process described above. However, whereas in the first charging process, the upper limit is the charging required energy Cneed, here it is the sum of the charging required energy Cneed and the surplus energy Cexed.

Then, the charge/discharge plan creation unit 215 creates a discharge plan with the surplus power amount Cexed obtained in step S5502 as the upper limit (step S5503). This discharge plan is also basically the same as the discharge plan creation process in the above-mentioned planning procedure 2.

As described above, in this embodiment, the power demand leveling system 100 includes a charge/discharge control device (PCS310) that controls the charging/discharging of the battery (EV battery 320) of the connected electric vehicle (EV) and a power management device 200 that controls the power demand of the entire business, and levels out the power demand of the business. The power management device 200 includes a charge/discharge plan creation unit 215 that creates a charge/discharge plan for the EV battery 320 so as to minimize the maximum daily power demand of the business based on the current SOC, which is the remaining capacity when the EV battery 320 is connected, and reservation information for the EV battery 320, and an instruction unit 216 that issues charge/discharge instructions to the PCS 310 according to the charge/discharge plan created by the charge/discharge plan creation unit 215.

In this embodiment, a charge/discharge plan is created based only on the remaining capacity at the time of connection and the reservation information. As long as there is no limit to the amount of discharge and the specified remaining capacity can be secured by the specified charging completion time, the remaining capacity may temporarily become lower than the specified remaining capacity in the process prior to that. This allows a larger amount of power to be used for discharging, making it possible to create a charge/discharge plan more flexibly and effectively.

In addition, in this embodiment, a comprehensive planning procedure is determined in advance and stored according to a predicted power demand curve, which is the power demand value for each specified time period on a target day that is predicted in advance. Then, when planning a charge/discharge plan, the charge/discharge plan planning unit 215 plans the charge/discharge plan according to this planning procedure.

Therefore, according to this embodiment, a charge/discharge plan can be created regardless of the shape of the predicted power demand curve or the change in the predicted power demand value. In other words, it is possible to achieve power demand leveling that is suitable for the model curve of power demand that differs from one business operator to another. And at the same time, mobility needs are not sacrificed. In this way, according to this embodiment, a planning procedure that is optimal for a wide variety of power demand curves can be used to maximize the reduction in peak load without sacrificing the mobility needs of electric vehicles.

For example, according to this embodiment, the EV battery 320 installed in an electric vehicle used by employees for commuting, etc., can be charged in the morning or evening when the office's power usage is low, and discharged during the daytime when power usage is at its peak, thereby reducing the peak power demand of the office without sacrificing mobility needs. In other words, the EV battery 320 can be effectively used as a storage battery and power supply source, and power demand can be optimized.

<Modification 1>
In the above embodiment, the period Td from the EV connection time Ts to the charging completion time Te is divided into three equal parts, and the pattern is determined and processed, but this is not limiting. For example, the processing may be performed without classifying into patterns. In this case, the charging plan is basically created from the earlier time, and then the discharging plan is created.

For example, a charging plan is created with a charging period being a predetermined time period tn during which the power demand value Ptn within the charging/discharging period Td, determined by the connection time Ts and the charging completion time Te, is smaller than the target power amount Ptgt, which is a predetermined target value, and a discharging plan is created with a predetermined time period tn during which the power demand value Ptn within the charging/discharging period Td is equal to or greater than the target power amount Ptgt.

<Modification 2>
Furthermore, the power demand leveling system 100 of the above embodiment and modified examples may be provided with a mode (charge/discharge frequency reduction mode) in which, when there is no impact on the contracted power (basic charge), a charge/discharge plan is formulated so as not to reduce the peak load by discharging the EV battery 320 and not to unnecessarily increase the number of times the EV battery 320 is charged/discharged.

It is generally known that an increase in the number of times the EV battery 320 is charged and discharged leads to the deterioration of the EV battery 320. As described above, the contracted power (basic charge) is determined by the maximum power demand value for each month of the past year. Therefore, if the maximum power demand value up to the planning date is not exceeded during the same month, there is no impact on the contracted power (basic charge). In such a case, there is no need to create a discharge plan to discharge and reduce peak loads, and only a charging plan needs to be created.

Specifically, for example, the power management device 200 further includes a reception unit that receives an instruction for the charge/discharge plan creation mode from the business operator, and receives an instruction from the business operator via the reception unit as to whether to create a charge/discharge plan in the normal mode or in the reduced charge/discharge frequency mode. Note that the normal mode is a mode in which the charge/discharge plan creation process described in the above embodiment is performed.

When an instruction for the charge/discharge count reduction mode is received, the charge/discharge plan creation unit 215 creates a charge/discharge plan in the charge/discharge count reduction mode. In the charge/discharge count reduction mode, the target power amount Ptgt in the above embodiment is set to the maximum power demand value during the same month up to the planning date, and a model pattern of the forecast power demand curve 510 for the planning date is determined. Subsequent processing is the same as in the above embodiment.

The present invention is not limited to the above-described embodiments, but includes various modified examples. The above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those having all of the configurations described. It is also possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

In addition, the above-mentioned configurations, functions, processing units, processing means, etc. may be realized in part or in whole in hardware, for example by designing them as integrated circuits. In addition, the above-mentioned configurations, functions, etc. may be realized in software by a processor interpreting and executing a program that realizes each function. Information such as programs, tables, files, etc. that realize each function may be stored in a memory, a recording device such as a hard disk or SSD, or a recording medium such as an IC card, SD card, or optical disk. In addition, the control lines and information lines shown are those that are considered necessary for explanation, and do not necessarily show all control lines and information lines in the product. For example, it may be considered that almost all of the configurations are actually connected to each other.

100: power demand leveling system, 110: HUB, 120: power meter, 130: system power, 150: business electrical system,
200: power management device, 211: EV reservation information acquisition unit, 212: battery information acquisition unit, 213: power usage acquisition unit, 214: power demand prediction unit, 215: charge/discharge plan creation unit, 216: instruction unit, 231: CPU, 232: memory, 233: storage device, 235: input/output I/F,
310: PCS, 311: PCS, 312: PCS, 313: PCS, 314: PCS, 320: EV battery, 321: EV battery, 322: EV battery, 323: EV battery, 324: EV battery,
410: EV reservation information DB, 411: EVID, 412: connection time, 413: charging completion time, 414: completion SOC, 415: PCSID, 420: battery information DB, 421: EVID, 422: battery capacity, 423: current SOC, 424: lower limit SOC, 425: upper limit SOC, 430: power usage history DB, 431: date, 432: time zone, 433: power usage Usage, 434: month, 435: maximum value, 440: charge/discharge plan DB, 441: planning date, 442: time period, 443: planned charge/discharge power amount, 444: EVID, 445: PCSID, 450: charge/discharge history DB, 451: date, 452: time period, 453: actual charge/discharge power amount, 455: PCSID, 456: original power usage amount, 457: predicted power demand value, 460: planning procedure DB,
510: predicted power demand curve, 510a: predicted power demand curve, 510b: predicted power demand curve, 510c: predicted power demand curve, 510d: predicted power demand curve, 510e: predicted power demand curve, 510f: predicted power demand curve, 510g: predicted power demand curve, 510h: predicted power demand curve, 512: charged amount, 513: discharged amount,
Cexed: surplus energy, Cfull: total energy, Cneed: energy required for charging, Ctotal: total charging amount, Ctn: charging amount, Dtn: discharging amount, PA: maximum value, PD: dischargeable energy amount, PCSmax: maximum chargeable amount, Pmax_0: power demand value, Pmax_1: maximum power demand value, Pmax_2: maximum power demand value, Pmax_3: maximum power demand value, Ptgt: target energy amount, Ptn: power demand value, Stn: available capacity, Stn2: available capacity, Td: period, Te: charging completion time, Ts: EV connection time, X: period, Y: period, Z: period, tn: time zone

Claims (5)

A power demand leveling system comprising: a charge/discharge control device that controls charging/discharging of a battery of an electric vehicle connected thereto; and a power management device that controls power demand of an entire business establishment, and the system levels out the power demand of the business establishment,
The power management device includes:
a charge/discharge plan creation unit that creates a charge/discharge plan for the battery that reduces a maximum value of a daily power demand of the business establishment based on a remaining capacity when the battery is connected and reservation information for the battery;
An instruction unit that issues a charge/discharge instruction to the charge/discharge control device according to the charge/discharge plan formulated by the charge/discharge plan formulation unit;
an electric power demand forecasting unit that forecasts an electric power demand value for each predetermined time period on a target day for which the charge/discharge plan is to be created as a forecast electric power demand curve;
a reservation information acquisition unit that acquires, as the reservation information, a charging completion time of the battery and a charging amount at the completion;
a battery information acquisition unit that acquires the specifications of the battery as battery information;
the charge/discharge plan formulation unit determines a charge amount and a discharge amount for the battery for each of the predetermined time periods using a connection time when the battery is connected, the connection time being detected by the charge/discharge control device, the predicted power demand curve, the reservation information, and the battery information;
creating the charge/discharge plan according to a predetermined planning procedure according to a shape of the predicted power demand curve in a chargeable/dischargeable period determined by the connection time and the charge completion time;
A power demand leveling system characterized by the above. 2. The power demand leveling system according to claim 1,
The charge/discharge plan creation unit creates a charging plan by setting a charging period to the predetermined time period during which the power demand value is smaller than a predetermined target value within a chargeable/dischargeable period determined by the connection time and the charging completion time.
A power demand leveling system characterized by the above. 3. The power demand leveling system according to claim 2,
The charge/discharge plan creation unit defines the predetermined time period during which the power demand value within the chargeable/dischargeable period is equal to or greater than the target value as a discharge period, and creates a discharge plan.
A power demand leveling system characterized by the above. 2. The power demand leveling system according to claim 1 ,
the battery is a plurality of batteries;
the charge/discharge plan creation unit creates the charge/discharge plan for each of the plurality of batteries in a predetermined order, and after creating a charge/discharge plan for one of the batteries, updates the predicted power demand curve by adding a change in the power demand value due to the charge/discharge plan to the predicted power demand curve, and creates a charge/discharge plan for the next battery.
A power demand leveling system characterized by the above. Computer,
a charge and discharge plan creating unit that creates a charge and discharge plan for a battery of an electric vehicle connected to a charge and discharge control device, the charge and discharge plan creating unit creating a charge and discharge plan for the battery that reduces a maximum value of a daily power demand of a business establishment equipped with the charge and discharge control device based on a remaining capacity of the battery when the battery is connected and reservation information for the battery;
An instruction unit that issues a charge/discharge instruction to the charge/discharge control device according to the charge/discharge plan;
an electric power demand forecasting unit that forecasts an electric power demand value for each predetermined time period on a target day for which the charge/discharge plan is to be created as a forecast electric power demand curve;
a reservation information acquisition unit that acquires, as the reservation information, a charging completion time of the battery and a charging amount at the completion;
a battery information acquisition unit that acquires the specifications of the battery as battery information;
The charge/discharge plan planning unit,
determining a charge amount and a discharge amount for the battery for each of the predetermined time periods using a connection time when the battery was connected, the connection time detected by the charge/discharge control device, the predicted power demand curve, the reservation information, and the battery information;
A program characterized by formulating the charge/discharge plan according to a predetermined planning procedure according to a shape of the predicted power demand curve for a chargeable/dischargeable period determined by the connection time and the charging completion time .

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