Power Control System

Abstract

To provide a power control system capable of appropriate managing power of an electromotive vehicle by efficiently using a time zone when electricity rates are low.SOLUTION: A vehicle control unit 24 calculates a proportion of a time period, as a standby rate WR, during an electromotive vehicle 3 is stopped in a state where a battery 22 can be charged form a power supply system 10 in a nighttime period within a period set in advance; selects a normal charging mode that allows charging in a daytime period and a nighttime period when a remaining electric amount SOC of the battery 22 is equal to or less than a first remaining amount threshold SOCth1 set in advance and the standby rate WR is less than a standby rate threshold WRth; and selects an eco charging mode that prohibits charging in the daytime period and allows charging in the nighttime period when the remaining electric amount SOC of the battery 22 is equal to or less than the first remaining amount threshold SOCth1 set in advance and the standby rate WR is equal to or greater than the standby rate threshold WRth.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power control system for externally charging a battery of an electric vehicle. [Background technology]

[0002] Electric vehicles, such as electric cars and plug-in hybrid cars, are equipped with an electric motor as a drive source and a battery as a power source for driving the electric motor. Electric vehicles have an external charging function for charging the battery with an external power supply. Generally, household power outlets and quick charging stations installed in various facilities are used as power supply sources. Furthermore, in recent electric vehicles, a power supply function (V2H function; Vehicle to Home function) has been put to practical use that not only charges the battery of the electric vehicle from a household power source, but also enables the power stored in the battery to be used as a household power source.

[0003] In this type of electric vehicle, it is desirable to charge the battery efficiently and at low cost by making the most effective use of time periods when electricity rates are low.Therefore, for example, Patent Document 1 discloses a technique for fully charging the battery by waiting for late-night hours (nighttime hours) when electricity rates are low when there is a surplus of electricity remaining in the battery, which is the amount of emergency electricity and the amount of reserved electricity (the amount of electricity required for the user to travel to and from a specified location in the daily living area). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2001-8380 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology disclosed in the above-mentioned Patent Document 1 is premised on the assumption that the electric vehicle is in a state in which it can be charged during late-night hours. Therefore, in electric vehicles that are often used during late-night hours, there is a risk that the opportunity to charge the battery may be missed.

[0006] The present invention has been made in consideration of the above circumstances, and has an object to provide a power control system that can perform appropriate power management for an electric vehicle by efficiently utilizing time periods when electricity usage rates are low. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided a power control system comprising: a power supply system connected to a commercial power supply, the first time period and a second time period having a cheaper unit price of electricity than the first time period, the battery provided in an electric vehicle; a standby rate calculation means for calculating a ratio of time during the second time period within a preset period during which the electric vehicle is stopped in a state in which power can be charged from the power supply system; and a mode selection means for selecting, as a charging mode for the battery, either a first charging mode that allows charging during the first time period and the second time period, or a second charging mode that prohibits charging during the first time period and allows charging during the second time period, the mode selection means automatically selecting the first charging mode when the remaining amount of electricity of the battery is equal to or less than a preset remaining amount threshold and the standby rate is less than a preset standby rate threshold, and automatically selecting the second charging mode when the remaining amount of electricity of the battery is equal to or less than the remaining amount threshold and the standby rate is equal to or greater than the standby rate threshold. Effect of the Invention

[0008] According to the power control system of the present invention, time periods when electricity rates are low can be efficiently utilized to perform appropriate power management for electric vehicles. [Brief description of the drawings]

[0009] [Figure 1] Schematic diagram showing the power control system of an electric vehicle [Diagram 2] Flowchart showing nighttime waiting rate calculation routine [Diagram 3] Flowchart showing the control mode selection routine by the automatic discrimination function (part 1) [Figure 4] Flowchart showing the control mode selection routine by the automatic discrimination function (part 2) [Diagram 5] Flowchart showing the control mode selection routine by manual operation (part 1) [Figure 6] Flowchart showing the control mode selection routine by manual operation (part 2) [Figure 7] Flowchart showing a charge / discharge control routine DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings relate to one embodiment of the present invention, and Fig. 1 is a schematic diagram showing a power control system for an electric vehicle.

[0011] The power control system 1 shown in FIG. 1 includes a power supply device 2 installed in a house or the like, and an electric vehicle 3 capable of being charged and discharged between the power supply device 2.

[0012] The power supply device 2 includes a power supply unit 15 and a power control unit 16.

[0013] The power supply / receiving unit 15 includes a coil and is installed on or in the ground. A switchboard 11 is connected to the power supply / receiving unit 15 via a first converter 17. As a result, the power supply / receiving unit 15 is connected via the switchboard 11 to a power supply system 10 of a commercial power source drawn into a house or the like.

[0014] Here, a commercial power source has a plurality of time periods throughout the day with different electricity unit prices set by an electric power company, etc. For example, the commercial power source of this embodiment has a first time period, which is a daytime period (e.g., 7:00 to 23:00), and a second time period, which is a nighttime period (e.g., 23:00 to 7:00), in which the electricity unit price is cheaper than the daytime period.

[0015] The power supply control unit 16 is configured using, for example, a microcomputer consisting of a CPU, ROM, RAM, etc., a reconfigurable integrated circuit such as an FPGA (Field Programmable Gate Array), or an integrated circuit custom-made for a specific application such as an ASIC (Application Specific Integrated Circuit).

[0016] The power supply control unit 16 monitors the power supply system 10 connected to a house or the like for abnormalities such as power outages.

[0017] An operation unit 18 for a user or the like to input various operations is connected to the power supply control unit 16. The operation unit 18 is provided with, for example, an automatic determination switch 18a for manually switching on / off an automatic determination function that automatically determines and performs charging / discharging between the power supply device 2 and the electric vehicle 3, a charge switch 18b for manually switching on / off charging from the power supply device 2 to the electric vehicle 3, and a discharge switch 18c for manually switching on / off discharging from the electric vehicle 3 to the power supply device 2.

[0018] The power supply control unit 16 is also provided with a vehicle detector 19. The vehicle detector 19 is configured to have, for example, a sonar sensor, a camera, an induction coil, or the like, and detects whether the electric vehicle 3 is parked (waiting) at a proper parking position set in advance. Here, the proper parking position of the electric vehicle 3 is a parking position set for the power supply / reception unit 15, and is a position where the electric vehicle 3 can charge and discharge between the power supply device 2.

[0019] The monitoring information of the power supply system 10, various operation information by the user and the like, and detection information of the electric vehicle 3 can be transmitted to the electric vehicle 3 via the communication antenna 16a.

[0020] Furthermore, the power supply control unit 16 receives control information related to charge / discharge control between the power supply device 2 and the electric vehicle 3 from the electric vehicle 3 via the communication antenna 16a. This control information includes control signals for the first converter 17, etc. Then, the power supply control unit 16 controls the first converter 17, etc. based on the received control signals, thereby performing charge / discharge control on the power supply device 2 side.

[0021] For example, when charging control is performed from the power supply device 2 to the electric vehicle 3, the power supply control unit 16 converts commercial power supplied from the switchboard 11 into high-frequency alternating current through control of the first converter 17, and outputs the converted power to the power supply / receiving unit 15. This enables the power supply / receiving unit 15 to generate a high-frequency electromagnetic field for supplying power to the electric vehicle 3.

[0022] Furthermore, for example, when discharge control is performed from the electric vehicle 3 to the power supply device 2, the power supply control unit 16, through control over the first converter 17, converts the high-frequency power received by the power supply / receiving unit 15 into a predetermined frequency (for example, the same frequency as commercial power) and outputs the converted power to the switchboard 11. This enables the power supply / receiving unit 15 to supply the power discharged from the electric vehicle 3 to the power supply system 10 of a house or the like.

[0023] The electric vehicle 3 is, for example, an electric car, and includes a motor 21 as a drive source, a battery 22, a power receiving unit 23, and a vehicle control unit 24.

[0024] The motor 21 is, for example, a three-phase AC synchronous motor with a permanent magnet embedded in the rotor. The motor 21 is connected to an inverter 25 configured with a three-phase bridge circuit or the like. The inverter 25 is also connected to the battery 22 via a control relay 26.

[0025] The inverter 25 receives electric power supplied from the battery 22 and rotates the motor 21. The driving force generated in the motor 21 is transmitted to driving wheels (for example, front wheels) via a transmission (not shown), thereby enabling the electric vehicle 3 to travel.

[0026] Furthermore, when the electric vehicle 3 is braked or decelerated, mechanical energy stored in the electric vehicle 3 as kinetic energy or potential energy is transmitted to the motor 21 via the drive wheels. This causes the motor 21 to function as a generator, and regenerative power generated in the motor 21 is stored in the battery 22.

[0027] The battery 22 is a rechargeable high-voltage DC battery, and is composed of, for example, a secondary battery such as a nickel-metal hydride or lithium ion battery, or a large-capacity capacitor such as an electric double-layer capacitor. The battery 22 stores the power received by the power receiving unit 23 and supplies it to the motor 21, and also stores the regenerative power generated by the motor 21. Furthermore, the battery 22 is also capable of supplying (discharging) the stored power to the power supply / receiving unit 15 via the power receiving unit 23.

[0028] The battery 22 is also provided with a battery controller 22a consisting of a microcomputer or the like. The battery controller 22a has a function of calculating a state of charge (SOC) of the battery 22 based on a charge / discharge current or the like detected by a current sensor (not shown) or the like. The SOC of the battery 22 is a ratio indicating the remaining amount of electricity in the battery 22, and is the ratio of the amount of stored electricity to the full charge capacity of the battery 22. For example, when the battery 22 is charged to the upper limit capacity, the SOC is calculated as 100%, and when the battery 22 is discharged to the lower limit capacity, the SOC is calculated as 0%.

[0029] The power supply / receiving unit 23 includes, for example, a coil, and is disposed at the rear bottom of the electric vehicle 3. For example, when the electric vehicle 3 is parked at a preset appropriate parking position, the power supply / receiving unit 23 faces the power supply / receiving unit 15 of the power supply device 2 and can be electromagnetically connected to the power supply / receiving unit 15. As a result, the power supply / receiving unit 23 of this embodiment wirelessly transmits and receives power to and from the power supply / receiving unit 15 by an electromagnetic induction method or a magnetic field resonance method using a coil.

[0030] The battery 22 is connected to the power receiving unit 23 via a second converter 27 .

[0031] The vehicle control unit 24 is configured using a microcomputer including a CPU, a ROM, a RAM, etc., an FPGA, an ASIC, or the like.

[0032] When the vehicle is traveling, the vehicle control unit 24 generates a control signal for driving the motor 21 with the control relay 26 turned on, and outputs the generated control signal to the inverter 25.

[0033] On the other hand, when the vehicle control unit 24 controls charging and discharging of power between the vehicle and the power supply device 2 external to the vehicle while the vehicle is stopped, the vehicle control unit 24 turns off the control relay 26.

[0034] For example, when charging control is performed from the power supply device 2 to the electric vehicle 3, the vehicle control unit 24, through control over the second converter 27, converts the high-frequency power received by the power receiving unit 23 from the power supply / receiving unit 15 into direct current and outputs it to the battery 22. This enables the power receiving unit 23 to charge the battery 22 with power from the power supply device 2.

[0035] Furthermore, for example, when discharge control is performed from the electric vehicle 3 to the power supply device 2, the vehicle control unit 24 converts the DC power supplied from the battery 22 into high-frequency AC through control of the second converter 27 and outputs it to the power receiving unit 23. This enables the power receiving unit 23 to generate a high-frequency electromagnetic field for supplying (discharging) power to the power supply device 2.

[0036] Incidentally, the control information for carrying out the above-mentioned charge control and discharge control is set in the vehicle control unit 24. It is also possible for the control information to be set in the power supply control unit 16 instead of the vehicle control unit 24.

[0037] Specifically, the vehicle control unit 24 receives, via a communication antenna 24a, monitoring information of the power supply system 10 transmitted from the power supply control unit 16, various operation information by a user or the like, and detection information of the electric vehicle 3. The vehicle control unit 24 also reads the SOC of the battery 22 from the battery controller 22a.

[0038] When the automatic discrimination switch 18a of the operation section 18 is turned on, the vehicle control unit 24 selects a control mode for the power supply device 2 and the electric vehicle 3 based on preset conditions. As this control mode, the vehicle control unit 24 can select a normal charging mode which is a first charging mode, an eco charging mode which is a second charging mode, a discharge mode, and a neutral mode. The vehicle control unit 24 sets control information related to charge / discharge control between the power supply device 2 and the electric vehicle 3 based on the selected control mode.

[0039] Prior to selecting these modes, the vehicle control unit 24 calculates the standby rate (nighttime standby rate) WR as the proportion of the time during which the electric vehicle 3 is parked in a state in which it can be charged from the power supply device 2 (power supply / receiving unit 15) during the nighttime hours within a preset period (e.g., the most recent week).

[0040] Then, the vehicle control unit 24 selects a control mode based on the calculated standby rate WR, monitoring information of the power supply system 10, the remaining charge SOC of the battery 22, detection information of the electric vehicle 3, and the like.

[0041] (1) The normal charging mode is a mode that is selected when, for example, the remaining charge SOC is equal to or less than a preset first remaining charge threshold SOCth1 (for example, about 20%) and the standby ratio WR of the electric vehicle 3 is less than a preset standby ratio threshold WRth. This normal charging mode is based on the premise that the electric vehicle 3 is parked in a state in which it can be charged and discharged (charged) between the power supply device 2 and that there is no abnormality in the power supply system 10.

[0042] Here, the standby rate threshold WRth is set based on the capacity of the battery 22, the time required to charge the battery 22, etc. In other words, the standby rate threshold WRth is set as a threshold for determining, from the standby rate WR, whether or not there is a high possibility that the predetermined charging can be performed only during the nighttime hours when the electric vehicle 3 is on standby.

[0043] Therefore, when the standby rate WR falls below the standby rate threshold WRth and the normal charging mode is selected, it is unlikely that the specified charging can be performed only during the nighttime hours. When such a normal charging mode is selected, charging is permitted for the battery 22 of the electric vehicle 3 regardless of whether it is day or night in order to ensure a sufficient charging time. When the remaining charge SOC becomes equal to or greater than a preset second remaining charge threshold SOCth2 (SOC near full charge, SOCth2>SOCth1), the normal charging mode ends and the control mode transitions to the neutral mode.

[0044] (2) The eco-charging mode is a mode that is selected, for example, when the state of charge (SOC) is equal to or less than a preset first remaining charge threshold SOCth1 (e.g., about 20%) and the waiting rate WR of the electric vehicle 3 is equal to or higher than a waiting rate threshold WRth. This eco-charging mode assumes that the electric vehicle 3 is parked in a state where it can be charged and discharged (charged) with the power supply device 2 and that there is no abnormality in the power supply system 10.

[0045] When the eco-charging mode is selected, charging of the battery 22 of the electric vehicle 3 is permitted only during the night time zone. That is, when the eco-charging mode is selected, even if the electric vehicle 3 is parked in a chargeable state during the day time zone, charging of the electric vehicle 3 is performed after waiting for the night time zone. Then, when the SOC becomes equal to or higher than a preset second remaining charge threshold SOCth2, or when a transition is made from the night time zone to the day time zone during charging, the eco-charging mode ends and the control mode shifts to the neutral mode.

[0046] (3) The discharging mode is a mode that is selected, for example, when the SOC is equal to or higher than a preset third remaining charge threshold SOCth3 (e.g., about 70%) and an abnormality such as a power outage has occurred in the power supply system 10. This discharging mode assumes that the electric vehicle 3 is parked in a state where it can be charged and discharged (discharged) with the power supply device 2.

[0047] When the discharging mode is selected, discharging from the battery 22 of the electric vehicle 3 to the power supply device 2 is performed. Then, when the SOC becomes equal to a preset fourth remaining charge threshold SOCth4 (SOCth4 < SOCth3), or when the abnormality in the power supply system 10 is recovered, the discharging mode ends and the control mode shifts to the neutral mode.

[0048] (4) The neutral mode is a mode that is selected in cases other than the above (1) to (3).

[0049] When the neutral mode is selected, charging and discharging between the power supply device 2 and the electric vehicle 3 is prohibited. The neutral mode ends when the control mode transitions to the normal charging mode, the eco charging mode, or the discharging mode described above.

[0050] Here, the selection of the normal charging mode and the deselection of the normal charging mode (transition from the normal charging mode to the neutral mode) can also be performed by turning on / off the charging switch 18b of the operation unit 18. Moreover, the selection of the discharge mode and the deselection of the discharge mode (transition from the discharge mode to the neutral mode) can also be performed by turning on / off the discharge switch 18c of the operation unit 18. The control mode selected based on these switch operations has priority over the automatically determined control mode.

[0051] In this manner, in this embodiment, the vehicle control unit 24 realizes the functions of a standby rate calculation means and a mode selection means.

[0052] Next, the calculation of the nighttime standby rate WR will be described with reference to a flowchart of a nighttime standby rate calculation routine. This routine is executed by the power supply control unit 16 at set time intervals.

[0053] When the routine starts, in step S101, the power supply control unit 16 checks whether the current time period is a nighttime period when the unit price of electricity is low.

[0054] Then, in step S101, if it is determined that the current time period is not a nighttime period, that is, if it is determined that the current time period is a daytime period, the power supply control unit 16 directly exits the routine.

[0055] On the other hand, if it is determined in step S101 that the current time period is a nighttime time period, the power supply control unit 16 proceeds to step S102 and determines the standby state of the electric vehicle 3. That is, the power supply control unit 16 determines, based on information from the vehicle detector 19, whether the electric vehicle 3 is parked at an appropriate parking position where it can be charged by the power supply device 2.

[0056] In the following step S103, the power supply control unit 16 updates the history data related to the standby state of the electric vehicle 3. That is, the power supply control unit 16 adds the standby state of the electric vehicle 3 determined in step S102 to the history data, and sequentially deletes past determination results that are older than a set period (e.g., one week) from the history data.

[0057] Then, when the process proceeds from step S103 to step S104, the power supply control unit 16 calculates the nighttime standby rate WR of the electric vehicle 3 based on the updated history data, and then exits the routine.

[0058] Next, the selection of the control mode by the automatic discrimination function will be described with reference to the flow chart of the control mode selection routine shown in Figures 3 and 4. This routine is repeatedly executed at set time intervals in the vehicle control unit 24 on the conditions that, for example, the automatic discrimination switch 18a of the operation unit 18 in the power supply device 2 is turned on, the electric vehicle 3 is stopped, and communication with the power supply control unit 16 is established through the communication antenna 24a.

[0059] When the routine starts, in step S201, the vehicle control unit 24 checks whether the power supply device 2 and the electric vehicle 3 are in a state in which charging and discharging are possible. That is, the vehicle control unit 24 checks whether the electric vehicle 3 is parked in an appropriate parking position where the power supply device 2 can be charged and discharged, based on detection information of the electric vehicle 3 transmitted from the power supply device 2.

[0060] Then, when it is determined in step S201 that the power supply device 2 and the electric vehicle 3 are not in a state capable of charging and discharging, the vehicle control unit 24 proceeds to step S214. Note that cases in which the power supply device 2 and the electric vehicle 3 are not in a state capable of charging and discharging are assumed to be, for example, cases in which the electric vehicle 3 detected by the vehicle detector 19 is not parked at an appropriate parking position, or cases in which the electric vehicle 3 has not been detected by the vehicle detector 19 in the first place.

[0061] On the other hand, if it is determined in step S201 that the power supply device 2 and the electric vehicle 3 are in a state in which charging and discharging are possible, the vehicle control unit 24 proceeds to step S202 and checks whether or not there is an abnormality in the power supply system 10, such as a power outage.

[0062] Then, if it is determined in step S202 that there is no abnormality in the power supply system 10, the vehicle control unit 24 proceeds to step S203 and checks whether or not a charging mode (i.e., normal charging mode or eco charging mode) is selected as the current control mode.

[0063] Then, if it is determined in step S203 that the charging mode is not selected as the current control mode, the vehicle control unit 24 proceeds to step S205 and checks whether the remaining electricity SOC is less than a preset first remaining electricity threshold SOCth1.

[0064] Then, in step S205, if it is determined that the remaining electricity SOC is equal to or greater than the first remaining amount threshold SOCth1, the vehicle control unit 24 proceeds to step S214.

[0065] On the other hand, if it is determined in step S205 that the remaining electricity SOC is less than the first remaining amount threshold SOCth1, the vehicle control unit 24 proceeds to step S206, and checks whether the nighttime standby rate WR of the electric vehicle 3 is equal to or greater than a preset standby rate threshold WRth.

[0066] Then, when it is determined in step S206 that the nighttime standby rate WR of the electric vehicle 3 is equal to or greater than the standby rate threshold WRth, the vehicle control unit 24 proceeds to step S207, selects the normal charging mode as the control mode, and then exits the routine.

[0067] On the other hand, if it is determined in step S206 that the nighttime standby rate WR of the electric vehicle 3 is greater than the standby rate threshold WRth, the vehicle control unit 24 proceeds to step S208, selects the eco-charging mode as the control mode, and then exits the routine.

[0068] Also, if it is determined in step S203 that the charging mode is selected as the current control mode, the vehicle control unit 24 proceeds to step S204 and checks whether the remaining electricity SOC is less than a preset second remaining electricity threshold SOCth2 (where SOCth2>SOCth1).

[0069] Then, in step S204, if it is determined that the remaining charge SOC is less than the second remaining charge threshold SOCth2, the vehicle control unit 24 exits the routine while maintaining the currently selected charging mode.

[0070] On the other hand, if it is determined in step S204 that the remaining electricity SOC is equal to or greater than the second remaining amount threshold SOCth2, the vehicle control unit 24 proceeds to step S214.

[0071] Furthermore, if it is determined in step S202 that there is an abnormality in the power supply system 10, the vehicle control unit 24 proceeds to step S209 to check whether or not the discharge mode has been selected as the current control mode.

[0072] Then, if it is determined in step S209 that the discharge mode is not selected as the current control mode, the vehicle control unit 24 proceeds to step S211 and checks whether the remaining electricity SOC is equal to or less than a preset third remaining electricity threshold SOCth3.

[0073] And, in step S211, when it is determined that the remaining electric quantity SOC is less than the third remaining quantity threshold value SOCth3, the vehicle control unit 24 proceeds to step S214.

[0074] On the other hand, in step S211, when it is determined that the remaining electric quantity SOC is greater than or equal to the third remaining quantity threshold value SOCth3, the vehicle control unit 24 proceeds to step S213, selects the discharge mode as the control mode, and then exits the routine.

[0075] Also, in step S209, when it is determined that the discharge mode is selected as the current control mode, the vehicle control unit 24 proceeds to step S210 to check whether the remaining electric quantity SOC is less than a preset fourth remaining quantity threshold value SOCth4 (where SOCth4 < SOCth3).

[0076] And, in step S210, when it is determined that the remaining electric quantity SOC is greater than or equal to the fourth remaining quantity threshold value SOCth4, the vehicle control unit 24 exits the routine while maintaining the current discharge mode.

[0077] On the other hand, in step S210, when it is determined that the remaining electric quantity SOC is less than the fourth remaining quantity threshold value SOCth4, the vehicle control unit 24 proceeds to step S214.

[0078] Also, when proceeding from step S201, step S204, step S205, step S210, or steps S211 to S214, the vehicle control unit 24 selects the neutral mode as the control mode and then exits the routine.

[0079] Next, regarding the control mode selection by manual operation, it will be described according to the control mode selection routine shown in FIGS. 5 and 6. This routine is repeatedly executed by the vehicle control unit 24 every set time, for example, on the condition that the electric vehicle 3 is stopped and communication with the power control unit 16 is established through the communication antenna 24a.

[0080] When the routine starts, the vehicle control unit 24 checks in step S301 whether or not the charging switch 18b of the operation unit 18 has been operated by a user or the like.

[0081] Then, when it is determined in step S301 that the charging switch 18b has not been operated, the vehicle control unit 24 proceeds to step S305.

[0082] On the other hand, if it is determined in step S301 that the charging switch 18b has been operated, the vehicle control unit 24 proceeds to step S302. If the automatic determination function of the current control mode is on, the vehicle control unit 24 cancels the automatic determination function and then proceeds to step S303. Note that when the automatic determination function is canceled, the execution of the control mode selection routine by the automatic determination function shown in Figs. 3 and 4 is canceled until the automatic determination switch 18a of the operation unit 18 is turned on by a user or the like.

[0083] When proceeding from step S302 to step S303, the vehicle control unit 24 checks whether the operation of the charging switch 18b determined in the above-mentioned step S301 was an ON operation.

[0084] Then, if it is determined in step S303 that the operation of the charging switch 18b is an OFF operation, the vehicle control unit 24 proceeds to step S309.

[0085] On the other hand, if it is determined in step S303 that the operation of the charging switch 18b is an on operation, the vehicle control unit 24 proceeds to step S304, selects the normal charging mode as the control mode, and then proceeds to step S305.

[0086] When proceeding from step S301 or step S304 to step S305, the vehicle control unit 24 checks whether or not the discharge switch 18c of the operation portion 18 has been operated by the user or the like.

[0087] Then, if it is determined in step S305 that the discharge switch 18c has not been operated, the vehicle control unit 24 proceeds to step S310.

[0088] On the other hand, if it is determined in step S305 that the discharge switch 18c has been operated, the vehicle control unit 24 proceeds to step S306. Then, if the automatic control mode determination function is currently on, the vehicle control unit 24 cancels the automatic determination function and then proceeds to step S307.

[0089] When proceeding from step S306 to step S307, the vehicle control unit 24 checks whether or not the operation of the discharge switch 18c determined in the above-mentioned step S305 was an ON operation.

[0090] Then, if it is determined in step S307 that the operation of the discharge switch 18c is an on operation, the vehicle control unit 24 proceeds to step S308, selects the discharge mode as the control mode, and then proceeds to step S310.

[0091] On the other hand, if it is determined in step S307 that the operation of the discharge switch 18c is an OFF operation, the vehicle control unit 24 proceeds to step S309.

[0092] When the process proceeds from step S303 or step S307 to step S309, the vehicle control unit 24 selects the neutral mode as the control mode, and then proceeds to step S310.

[0093] When the process proceeds from step S305, step S308, or step S309 to step S310, the vehicle control unit 24 checks whether the automatic determination of the control mode is currently being cancelled.

[0094] If it is determined in step S310 that the automatic determination is not being cancelled, the vehicle control unit 24 exits the routine.

[0095] On the other hand, if it is determined in step S310 that the automatic determination is being canceled by manual operation of the charging switch 18b or the discharging switch 18c, etc., the vehicle control unit 24 proceeds to step S311 and checks whether the normal charging mode is currently selected by manual operation of the user, etc.

[0096] Then, when it is determined in step S311 that the manual charging mode is not selected, the vehicle control unit 24 proceeds to step S313.

[0097] On the other hand, if it is determined in step S311 that the normal charging mode is selected, the vehicle control unit 24 proceeds to step S312 and checks whether the remaining amount of electricity SOC is less than a preset second remaining amount threshold SOCth2.

[0098] Then, in step S312, if it is determined that the remaining electricity SOC is equal to or greater than the second remaining amount threshold SOCth2, the vehicle control unit 24 proceeds to step S315.

[0099] On the other hand, if it is determined in step S312 that the remaining amount of electricity SOC is less than the second remaining amount threshold SOCth2, the vehicle control unit 24 proceeds to step S313.

[0100] When the process proceeds from step S311 or step S312 to step S313, the vehicle control unit 24 checks whether or not the discharge mode is currently being selected by a manual operation by the user or the like.

[0101] Then, if it is determined in step S313 that the discharge mode is not selected, the vehicle control unit 24 exits the routine.

[0102] On the other hand, if it is determined in step S313 that the discharge mode is selected, the vehicle control unit 24 proceeds to step S314 and checks whether the remaining amount of electricity SOC is less than the fourth remaining amount threshold SOCth4.

[0103] Then, in step S314, if it is determined that the remaining electricity SOC is equal to or greater than the remaining electricity threshold SOCth4, the vehicle control unit 24 exits the routine.

[0104] On the other hand, if it is determined in step S314 that the remaining electricity SOC is less than the fourth remaining amount threshold SOCth4, the vehicle control unit 24 proceeds to step S315.

[0105] When the process proceeds from step S312 or step S314 to step S315, the vehicle control unit 24 selects the neutral mode as the control mode, and then exits the routine.

[0106] Next, the charge / discharge control based on the currently selected control mode will be described with reference to the flowchart of the charge / discharge control routine shown in Fig. 7. This routine is repeatedly executed at set time intervals by the vehicle control unit 24 on the condition that, for example, the electric vehicle 3 is stopped and communication with the power supply control unit 16 is established via the communication antenna 24a.

[0107] When the routine starts, the vehicle control unit 24 checks in step S401 whether or not the charging mode is currently selected as the control mode.

[0108] Then, if it is determined in step S401 that the charge mode has not been selected, that is, if it is determined that the discharge mode or the neutral mode has been selected as the control mode, the vehicle control unit 24 proceeds to step S405.

[0109] On the other hand, if it is determined in step S401 that the charging mode has been selected, the vehicle control unit 24 proceeds to step S402 and checks whether the selected charging mode is the normal charging mode.

[0110] Then, if it is determined in step S402 that the normal charging mode has been selected, the vehicle control unit 24 proceeds to step S404.

[0111] On the other hand, if it is determined in step S402 that the normal charging mode has not been selected, that is, that the eco charging mode has been selected, the vehicle control unit 24 proceeds to step S403 and checks whether the current time period is a nighttime period.

[0112] Then, in step S403, if it is determined that the current time period is not a nighttime period but a daytime period, the vehicle control unit 24 exits the routine.

[0113] On the other hand, if it is determined in step S403 that the current time period is a nighttime time period, the vehicle control unit 24 proceeds to step S404.

[0114] When the process proceeds from step S402 or step S403 to step S404, the vehicle control unit 24 performs charging control for the electric vehicle 3 from the power supply device 2, and then exits the routine. That is, in step S404, the vehicle control unit 24 sets control information for performing charging control based on the currently selected control mode (normal charging mode or eco charging mode). Then, the vehicle control unit 24 transmits the set control information to the power supply control unit 16, thereby controlling the first converter 17 and the like through the power supply control unit 16. In addition, the vehicle control unit 24 controls the second converter 27 based on the set control information. As a result, the power supplied from the power supply system 10 is transmitted from the power supply / receiving unit 15 to the power supply / receiving unit 23, and the battery 22 is charged.

[0115] Furthermore, when the process proceeds from step S401 to step S405, the vehicle control unit 24 checks whether or not the discharge mode is currently selected as the control mode.

[0116] Then, in step S405, if it is determined that the discharge mode has not been selected, that is, if it is determined that the neutral mode has been selected, the vehicle control unit 24 directly exits the routine.

[0117] On the other hand, if it is determined in step S405 that the discharge mode is selected, the vehicle control unit 24 proceeds to step S406, performs discharge control from the electric vehicle 3 to the power supply device 2, and then exits the routine. That is, in step S406, the vehicle control unit 24 sets control information for performing discharge control based on the currently selected control mode (discharge mode). Then, the vehicle control unit 24 transmits the set control information to the power supply control unit 16, thereby controlling the first converter 17 and the like through the power supply control unit 16. Furthermore, the vehicle control unit 24 controls the second converter 27 based on the set control information. As a result, the power stored in the battery 22 is transmitted from the power receiving unit 23 to the power supply / receiving unit 15, and power is supplied to the power supply system 10 during a power outage or the like.

[0118] According to this embodiment, the vehicle control unit 24 calculates the ratio of time during which the electric vehicle 3 is parked in a state in which the battery 22 can be charged from the power supply system 10 during nighttime hours within a preset period (for example, one week), as the standby rate WR, and selects a normal charging mode that allows charging during daytime hours and nighttime hours when the remaining charge SOC of the battery 22 is equal to or less than the preset first remaining charge threshold SOCth1 and the standby rate WR is less than the standby rate threshold WRth, and selects an eco charging mode that prohibits charging during daytime hours and allows charging during nighttime hours when the remaining charge SOC of the battery 22 is equal to or less than the preset first remaining charge threshold SOCth1 and the standby rate WR is equal to or greater than the standby rate threshold WRth, thereby making it possible to efficiently use time periods when electricity usage rates are low and to perform appropriate power management of the electric vehicle 3.

[0119] That is, the vehicle control unit 24 judges whether or not it is highly likely that the charging time can be covered only during the nighttime hours based on the standby rate WR during the nighttime hours within the most recent set period. If the vehicle control unit 24 judges that it is highly likely that the charging time can be covered only during the nighttime hours, it selects the eco-charging mode. This allows the electric vehicle 3 to be efficiently charged by utilizing the time period when the electricity usage fee is low.

[0120] On the other hand, when it is determined that the charging time of the electric vehicle 3 is unlikely to be covered only during the nighttime hours, the normal charging mode is selected. This ensures a sufficient charging time even when the standby rate WR is low, and the charge amount of the battery 22 of the electric vehicle 3 can be maintained at an appropriate level.

[0121] These determinations can be made automatically in the vehicle control unit 24 based on the standby rate WR, so that appropriate power management can be achieved without bothering the user or the like.

[0122] In this case, when a charge or discharge instruction is given by a user or the like through an operational input to the operation unit 18, a control mode based on the instruction from the user or the like is prioritized instead of the mode selected by automatic determination, thereby realizing charge and discharge control that respects the will of the user or the like, as necessary, while assuming charge and discharge control based on the automatically determined control mode.

[0123] The invention described in the above embodiments is not limited to those embodiments, and various modifications can be made in the implementation stage without departing from the gist of the invention. Furthermore, each of the above embodiments includes inventions at various stages, and various inventions can be extracted by appropriate combinations of the disclosed constituent elements.

[0124] For example, if some of the constituent elements shown in the embodiment can be deleted and the problem described can be solved and the effect described can be obtained, the configuration from which the constituent elements have been deleted can be extracted as an invention. [Explanation of symbols]

[0125] 1 … Power control system 2 … Power supply device 3 … Electric vehicles 10 … Power system 11 … Switchboard 15 ... Power supply unit 16 … Power supply control unit 16a … Communication antenna 17 … First converter 18 … Operation section 18a … Automatic detection switch 18b … Charging switch 18c … Discharge switch 19 … Vehicle detector 21 ... Motor 22 … Battery 22a … Battery controller 23 ... Power receiving unit 24 … Vehicle control unit 24a … Communication antenna 25 … Inverter 26 … Control relay 27 … Second converter

Claims

1. a power supply system connected to a commercial power supply, the power supply system having a first time period and a second time period in which the unit price of electricity is cheaper than that of the first time period as time periods in one day; A battery provided in the electric vehicle; a standby rate calculation means for calculating a rate of a time during which the electric vehicle is stopped in a state in which power can be charged from the power supply system to the battery during the second time period within a preset period as a standby rate; a mode selection means for selecting, as a charging mode for the battery, either a first charging mode that permits charging during the first time period and the second time period, or a second charging mode that prohibits charging during the first time period and permits charging during the second time period, a mode selection means for automatically selecting the first charging mode when the remaining charge of the battery is equal to or less than a predetermined first remaining charge threshold and the standby rate is less than a predetermined standby rate threshold, and for automatically selecting the second charging mode when the remaining charge of the battery is equal to or less than the first remaining charge threshold and the standby rate is equal to or more than the standby rate threshold.

2. a charging switch for manually switching on or off charging of the battery; 2. The power control system according to claim 1, wherein the mode selection means selects the second charging mode when the charging switch is turned on.

3. 3. The power control system according to claim 1, wherein the mode selection means selects a neutral mode to prohibit charging when the remaining charge of the battery becomes equal to or greater than a second remaining charge threshold that is greater than the first remaining charge threshold and is set closer to full charge while the first charging mode or the second charging mode is selected.

4. The power control system according to any one of claims 1 to 3, characterized in that the mode selection means selects a discharge mode in which power is discharged from the battery to the power supply system when an abnormality is detected in the power supply system and the remaining charge of the battery is equal to or greater than a predetermined third remaining charge threshold.

5. The power control system according to claim 4, characterized in that the mode selection means, when the remaining amount of electricity of the battery becomes less than a fourth remaining amount threshold that is preset to a value smaller than the third remaining amount threshold while the discharge mode is selected, selects a neutral mode to prohibit the discharge.

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