Electric vehicle charging system, power management device, and electric vehicle charging method

Abstract

An electric vehicle charging system (300) comprises: a charging station (6) equipped with chargers (601) that can charge electric vehicles by using power supplied from a private line (9); electric power substation equipment that supplies power to the private line (9) and a feeder (5); a power converter (8) that is installed between the feeder (5) and the private line (9) and steps down the power supplied from the feeder (5) to the private line (9); and a power management device (50) that manages the power supplied to the charging station (6) by controlling the electric power substation equipment and the power converter (8). The power management device (50) estimates, on a per-time-band basis, the power that a train (4) connected to the feeder (5) uses during powering, the regenerative power generated during braking of the train (4), and the available capacity of the electric power substation equipment, and controls, on the basis of the estimations, the electric power substation equipment and the power converter (8) so that the power supplied to the electric power substation equipment does not exceed a preset rated capacity.

Description

[Technical Field]

[0001] The present disclosure relates to an electric vehicle charging system for charging the battery of an electric vehicle, a power management device used in the system, and an electric vehicle charging method. [Background technology]

[0002] Electric vehicles (EVs) require a large amount of power to charge, which places a heavy burden on both the amount of power consumed and peak demand. For this reason, attempts have been made to save energy by using regenerative power from railways to charge EVs.

[0003] In the electric vehicle charging system disclosed in Patent Document 1, an electric vehicle charging device is connected to a railway feeder, and regenerative power generated when the train brakes is collected and stored in a power storage device, which is then used to charge the electric vehicle. This method saves energy because regenerative power that is normally wasted is used to charge the electric vehicle. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-080628 Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, because charging electric vehicles requires high peak power, if multiple high-capacity chargers are installed to meet the charging demands of multiple electric vehicles, it is necessary to install high-capacity substation equipment that can handle the peak power required for charging electric vehicles, which poses the issue of increased costs.

[0006] For example, the capacity of substation equipment for railway power feeder systems is designed to match the peak power required by trains. Therefore, when connecting electric vehicle charging equipment to railway feeder lines, the capacity of the substation equipment must be significantly increased to add electric vehicle charging equipment with high peak power demands, resulting in high costs.

[0007] On the other hand, if electric vehicles are charged using only regenerative power when it is being generated, there is no need to increase the capacity of the substation equipment. However, the time periods during which regenerative power is generated and the amount of regenerative power that can be generated are limited, which reduces the number of electric vehicles that can be charged.

[0008] The present disclosure has been made in consideration of the above, and aims to provide an electric vehicle charging system that increases the number of electric vehicles that can be charged without increasing the capacity of substation equipment. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems and achieve the object, the electric vehicle charging system according to the present disclosure includes a charging station equipped with a charger capable of charging an electric vehicle using power supplied from a private line, a substation that supplies power to the private line and a feeder line, a power converter installed between the feeder line and the private line and that steps down the power supplied from the feeder line to the private line, and a power management device that manages the power supplied to the charging station by controlling the substation and the power converter. The power management device predicts, for each time period, the power used by a train connected to the feeder line when powering, the regenerative power generated when the train brakes, and the available capacity of the substation, and based on the predictions, controls the substation and the power converter so that the power supplied to the substation does not exceed a preset rated capacity. [Effects of the Invention]

[0010] The present disclosure has an effect of providing an electric vehicle charging system that increases the number of electric vehicles that can be charged without increasing the capacity of the substation equipment. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing the configuration of an electric vehicle charging system according to a first embodiment. [Figure 2] FIG. 1 is a diagram illustrating the operation of a power management device and an electric vehicle operation management device in an electric vehicle charging system according to a first embodiment. [Figure 3] FIG. 1 is a diagram showing the configuration of a power management device of an electric vehicle charging system according to a first embodiment. [Figure 4] FIG. 1 is a diagram showing the configuration of an electric vehicle operation management device according to a first embodiment. [Figure 5] FIG. 1 is a diagram showing an example of power generated in an electric vehicle charging system according to the first embodiment. [Figure 6] 1 is a flowchart showing the flow of operations of a power management device and an electric vehicle operation management device of an electric vehicle charging system according to a first embodiment. [Figure 7] FIG. 10 is a diagram showing the configuration of an electric vehicle charging system according to a second embodiment. [Figure 8] FIG. 10 is a diagram showing an example of power generated in an electric vehicle charging system according to a second embodiment. [Figure 9] FIG. 10 is a diagram showing the configuration of an electric vehicle charging system according to a third embodiment. [Figure 10] FIG. 10 is a diagram showing an example of power generated in an electric vehicle charging system according to a third embodiment. [Figure 11] FIG. 1 is a diagram showing an example of a hardware configuration of a power management device of an electric vehicle charging system according to any one of first to third embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0012] An electric vehicle charging system, a power management device, and an electric vehicle charging method according to embodiments will be described in detail below with reference to the drawings.

[0013] Embodiment 1 Fig. 1 is a diagram showing the configuration of an electric vehicle charging system according to embodiment 1. Fig. 2 is a diagram showing a schematic diagram of the operation of a power management device and an electric vehicle operation management device in the electric vehicle charging system according to embodiment 1. An electric vehicle charging system 300 according to embodiment 1 includes a charging station 6 for charging an electric vehicle 600, a private line 9 laid by an installer of the charging station 6, a main substation 1 connected to the power grid, and a feeding substation 2 and a private line substation 3 connected to the main substation 1.

[0014] The electric vehicle charging system 300 also includes a solar power generation facility 7 connected to a private line 9 via a power converter 701, a power converter 8 installed between the feeder line 5 and the private line 9, a power management device 50 that manages the power supplied to the charging station 6, and an electric vehicle operation management device 60 that manages the operation of the electric vehicle 600.

[0015] In electric vehicle charging system 300, main substation 1, feeding substation 2, and private line substation 3 are substation facilities that supply power to private lines 9 and feeders 5. Main substation 1 steps down the voltage of AC power P1 supplied from the power grid and outputs it. Feeding substation 2 steps down the voltage of AC power P2 supplied from main substation 1 and converts it to DC, and supplies it to feeders 5 for supplying power to trains 4. Private line substation 3 steps down the voltage of AC power P3 supplied from main substation 1 and supplies it to private lines 9. In electric vehicle charging system 300 according to the first embodiment, the current flowing through private lines 9 is AC.

[0016] The power P1 supplied to the main substation 1 is the sum of the power P2 supplied to the feeding substation 2 and the power P3 supplied to the private line substation 3.

[0017] The charging station 6 includes a charger 601 for charging the electric vehicle 600, a storage battery 602 for storing power, a power converter 604 for stepping down the power that charges the storage battery 602 and stepping up the power that the storage battery 602 discharges, and a power converter 603 for converting the power supplied from the private line 9 to DC and stepping down the power.

[0018] The power management device 50 communicates with the charger 601, power converter 603, and power converter 604, and charges the electric vehicle 600, charges and discharges the storage battery 602, and supplies power from the private line 9 to the charging station 6. The electric vehicle operation management device 60 communicates with each of the multiple electric vehicles 600 and instructs them to operate based on a preset operation schedule.

[0019] The feeding substation 2 includes a transformer 201 and a rectifier 202. Electric power P2 supplied to the feeding substation 2 is stepped down by the transformer 201, and is then converted to DC power by the rectifier 202 and supplied to the feeder line 5 as DC power. The train 4 exchanges DC power with the feeder line 5.

[0020] Regarding the power P4 exchanged between the feeder 5 and the train 4, the power supplied from the feeder 5 to the train 4 is defined as positive power, and the power supplied from the train 4 to the feeder 5 is defined as negative power. When the train 4 is powered, the train 4 receives the power P4 from the feeder 5, so the power P4 is positive. On the other hand, when the train 4 brakes, regenerative power obtained by converting kinetic energy into electrical energy is supplied from the train 4 to the feeder 5, so the power P4 is negative.

[0021] The power converter 8 converts the power supplied from the feeder 5 to the private line 9 into AC power and boosts its voltage. When regenerative power generated by the train 4 is recovered by the feeder 5, power P5 is supplied from the feeder 5 to the private line 9 via the power converter 8. The solar power generation facility 7 generates solar power. The power converter 701 converts the power obtained by solar power generation in the solar power generation facility 7 into AC power and boosts its voltage, and supplies the solar-generated power P7 to the private line 9. Therefore, the private line 9 is supplied with power P3 obtained by stepping down the voltage of power P3 in the private line substation 3, power P5 supplied from the feeder 5 through the power converter 8 by the feeder 5 recovering regenerative power, and solar-generated power P7 obtained by boosting the power generated by solar power generation in the solar power generation facility 7.

[0022] Charging station 6 is supplied with power P6 from private line 9 via power converter 603. Power P6 supplied to charging station 6 is the sum of power P3 stepped down in private line substation 3, solar-generated power P7, and regenerated power P5.

[0023] 3 is a diagram showing the configuration of a power management device of the electric vehicle charging system according to Embodiment 1. The power management device 50 includes a control unit 51 that controls the charger 601, the storage battery 602, the power converter 603, the power converter 604, the power converter 8, the feeding substation 2, and the private line substation 3, and a processing unit 52 that creates a maximum charging power table that indicates, for each time period, the maximum power that can be supplied to the charger 601 by controlling the charging and discharging of the storage battery 602, and a charging fee table that indicates, for each time period, the charging fee for the electric vehicle 600. The processing unit 52 includes a photovoltaic power generation amount prediction unit 521 that predicts the amount of photovoltaic power generation P7, a regenerative power amount prediction unit 522 that predicts the amount of regenerative power, a substation available capacity prediction unit 523 that predicts the available capacity of the main substation 1, and a table creation unit 524 that creates the maximum charging power table and the charging fee table.

[0024] 4 is a diagram showing the configuration of an electric vehicle traffic management device according to embodiment 1. Electric vehicle traffic management device 60 includes a control unit 61 that dispatches electric vehicles 600, and a processing unit 62 that creates a charging plan for electric vehicles 600. Processing unit 62 includes a charging demand prediction unit 621 that predicts charging demand for electric vehicles 600, and a charging plan creation unit 622 that creates a charging plan for electric vehicles 600.

[0025] FIG. 5 is a diagram showing an example of power generated in the electric vehicle charging system according to the first embodiment. In FIG. 5, the vertical axis represents power, and the horizontal axis represents time. Time period T1 is a time period when train 4 is stopped, and power P2 supplied to feeding substation 2 is small. Time period T2 is a time period when train 4 is powering, and power P2 supplied to feeding substation 2 is large. Time period T3 is a time period when train 4 is coasting, and power P2 supplied to feeding substation 2 is small. Time period T4 is a time period when train 4 is braking, and regenerative power is supplied from train 4 to feeder line 5, so power P4 exchanged between train 4 and feeder line 5 is negative.

[0026] By controlling the charger 601, the storage battery 602, the power converter 603, the power converter 604, the power converter 8, and the power converter 701, the power management device 50 supplies power P3 to the private line substation 3 without restriction during time periods T1 and T3 when the power P2 supplied to the power feeding substation 2 is small, and suppresses the power P3 supplied to the private line substation 3 during time period T2 when the power P2 received by the power feeding substation 2 is large.

[0027] The power P2 supplied to the feeding substation 2 peaks during time period T2 when the train 4 is powered. Meanwhile, during time period T2 when the power P2 supplied to the feeding substation 2 is high, the power management device 50 suppresses the power P3 supplied to the private line substation 3. Therefore, the peak of the power P3 occurs during time period T1 or T3 when the power P2 supplied to the feeding substation 2 is low. By shifting the peak of the power P2 and the peak of the power P3 in this way, even if the sum of the peak power value of the power P2 supplied to the feeding substation 2 and the peak power value of the power P3 supplied to the private line substation 3 exceeds the rated capacity Pn1 of the main substation 1, the power P1 supplied to the main substation 1 can be kept below the rated capacity Pn1. This allows the number of chargeable electric vehicles 600 to be increased without upgrading the main substation 1 to increase its rated capacity.

[0028] Next, the operation of the power management device 50 and the electric vehicle traffic management device 60 that realize the control described above will be described. FIG. 6 is a flowchart showing the flow of operation of the power management device and the electric vehicle traffic management device of the electric vehicle charging system according to the first embodiment. In step S1, the solar power generation amount prediction unit 521 predicts the amount of power generated by the solar power generation facility 7 based on a weather forecast. Next, in step S2, the regenerative power amount prediction unit 522 predicts the amount of power used by the train 4, the amount of regenerative power generated, and the time period during which the regenerative power will be generated based on railway operation information. The railway operation information includes predicted data on the train 4's schedule and the number of passengers. For example, the regenerative power amount prediction unit 522 predicts the amount of power used by the train 4 and the time period during which the train 4 will use power by estimating the time period during which the train 4 will brake based on the railway operation information. In addition, the regenerative power amount prediction unit 522 predicts the amount of regenerative power generated and the time period during which the regenerative power will be generated by estimating the time period during which the train 4 will brake based on the railway operation information. Furthermore, the substation available capacity prediction unit 523 predicts the available capacity of the main substation 1. For example, the substation available capacity prediction unit 523 estimates the time period during which the train 4 will be powered based on railway operation information, and predicts the power P2 supplied to the feeding substation 2, the power P3 supplied to the private line substation 3, and the power P1 supplied to the main substation 1, which is the sum of the power P2 and the power P3. The substation available capacity prediction unit 523 estimates the available capacity relative to the rated capacity Pn1 of the main substation 1, based on the power P1 supplied to the main substation 1, the power P2 supplied to the feeding substation 2, and the power P3 supplied to the private line substation 3.

[0029] In step S3, the table creation unit 524 creates a maximum charging power table and a charging fee table. As described above, the power P3 that can be supplied by the private line substation 3 is restricted for each time period depending on the power P2 supplied to the feeding substation 2. Therefore, the maximum power that can be supplied to the charging station 6 varies for each time period depending on the power P2 supplied to the feeding substation 2, the solar-generated power P7 supplied from the solar power generation facility 7, and the power P5 resulting from regenerative power supplied from the train 4. The table creation unit 524 creates a maximum charging power table as a table for each time period regarding the maximum power that can be supplied to the charger 601 by charge / discharge control of the storage battery 602 installed in the charging station 6, based on the power P2 supplied to the feeding substation 2, the solar-generated power P7 supplied from the solar power generation facility 7, and the power P5 resulting from regenerative power supplied from the train 4.

[0030] The charging fee table is created based on the maximum charging power table, the predicted value of solar-generated power P7, and the predicted value of regenerated power. To maximize the use of solar-generated power P7 and regenerated power P5 for charging the electric vehicle 600, the charging fee is set low during time periods when solar-generated power P7 and regenerated power are abundant. Furthermore, during time periods when the train 4 is powering and the power P2 supplied to the feeding substation 2 is high, the available capacity of the main substation 1 is small and the maximum charging power is small. To avoid a concentration of charging demand during such time periods when the maximum charging power is small, the charging fee is set high. In this way, the table creation unit 524 optimizes the charging plan for the electric vehicle 600 by setting different variable charging fees for each time period based on the maximum charging power based on the available capacity of the main substation 1, the solar-generated power P7, and the predicted value of regenerated power.

[0031] In step S4 , the control unit 51 transmits the maximum charging power table and the charging fee table created by the table creation unit 524 to the electric vehicle operation management device 60 .

[0032] Meanwhile, in step S11, in the electric vehicle operation management device 60, the charging demand prediction unit 621 predicts the charging demand of the electric vehicle 600 based on the electric vehicle operation information. For example, if the electric vehicle 600 is a bus, the electric vehicle operation information includes a bus schedule and predicted data on the number of bus passengers. Also, for example, if the electric vehicle 600 is a taxi, the electric vehicle operation information includes predicted data on the number of taxi passengers and the transportation distance. Also, for example, if the electric vehicle 600 is a private car, the electric vehicle operation information includes predicted data on traffic information indicating the degree of road congestion.

[0033] In step S12, the control unit 61 of the electric vehicle operation management device 60 receives the maximum charging power table and the charging fee table transmitted from the power management device 50. In step S13, the charging plan creation unit 622 creates a charging plan for the electric vehicle 600 whose operation it manages, based on the maximum charging power table and the charging fee table. For example, the charging plan creation unit 622 creates a charging plan such that charging of the electric vehicle 600 is given priority during time periods when the charging fee for the electric vehicle 600 is set low. In step S14, the control unit 61 transmits the charging plan created by the charging plan creation unit 622 to the power management device 50.

[0034] In step S5, the control unit 51 of the power management device 50 receives the charging plan transmitted from the electric vehicle operation management device 60. The power management device 50 displays the charging plan received from the electric vehicle operation management device 60 on a display unit (not shown) or makes it public via the Internet, thereby enabling users of electric vehicles 600 whose operation is not managed by the electric vehicle operation management device 60 to know the degree of congestion at the charging station 6 in advance.

[0035] With the above, the operations of the power management device 50 and the electric vehicle operation management device 60 before the start of business are completed.

[0036] The above operation is repeatedly performed at preset time intervals even after business hours have started. For example, the operation is performed while making successive corrections in response to at least one of changes in the weather forecast, delays in train or bus schedules, and updates to electric vehicle operation information. By performing such operation, the electric vehicle charging system 300 according to the first embodiment can increase the number of electric vehicles 600 that can be charged without increasing the capacity of the main substation equipment 1.

[0037] The electric vehicle charging system 300 according to the first embodiment predicts the power consumption of the train 4 connected to the feeder line 5 when it is powering, the regenerative power generated when the train 4 is braking, and the available capacity of the main substation 1 for each time period, and based on the predictions, controls the feeding substation 2 and the power converter 8 so that the power supplied to the main substation 1 does not exceed a preset rated capacity. This makes it possible to increase the number of electric vehicles 600 that can be charged without having to perform equipment upgrades that increase the rated capacity of the main substation 1.

[0038] Embodiment 2 7 is a diagram showing the configuration of an electric vehicle charging system according to embodiment 2. Only the parts that differ from electric vehicle charging system 300 according to embodiment 1 will be described, and a description of the parts in common will be omitted.

[0039] In electric vehicle charging system 300 according to the second embodiment, the current flowing through private power line 9 is direct current. In electric vehicle charging system 300 according to the second embodiment, feeding substation equipment 2 steps down and directs power P2 supplied from main substation equipment 1, and supplies the direct current power to feeder line 5. Power converter 8 is installed between feeder line 5 and private power line 9. Power is supplied to private power line 9 from feeding substation equipment 2 via power converter 8. When regenerative power generated when train 4 brakes is recovered by feeder line 5, the regenerative power is stepped down by power converter 8 and supplied to private power line 9 as power P5. Power converter 603 steps down the power supplied from private power line 9. Power converter 701 boosts the power obtained by solar power generation in solar power generation equipment 7, and supplies solar-generated power P7 to private power line 9.

[0040] FIG. 8 is a diagram showing an example of power generated in the electric vehicle charging system according to the second embodiment. In FIG. 8, the vertical axis represents power, and the horizontal axis represents time. Power P2 is power supplied to the feeding substation 2 from the main substation 1. Power P4 is power exchanged between the train 4 and the feeder line 5. Power P5 is power supplied from the feeder line 5 to the private line 9 via the power converter 8.

[0041] As in embodiment 1, with regard to the power P4 exchanged between the feeder 5 and the train 4, the power supplied from the feeder 5 to the train 4 is defined as positive power, and the power supplied from the train 4 to the feeder 5 is defined as negative power.

[0042] Time period T1 is a time period when train 4 is stopped, and the positive power P4 supplied to train 4 from feeder 5 is small. Time period T2 is a time period when train 4 is powering, and the positive power P4 supplied to train 4 from feeder 5 is large. Time period T3 is a time period when train 4 is coasting, and the positive power P4 supplied to train 4 from feeder 5 is small. Time period T4 is a time period when train 4 is braking, and negative power is supplied from train 4 to feeder 5.

[0043] The power management device 50 controls the charger 601, the storage battery 602, the power converter 603, the power converter 604, and the power converter 8 so that the power converter 8 supplies power P5 from the feeder 5 to the private line 9 during time periods T1 and T3 when the positive power supplied from the feeder 5 to the train 4 is small and during time period T4 when negative power is supplied from the train 4 to the feeder 5, and controls to suppress the power P5 supplied from the feeder 5 to the private line 9 during time period T2 when the positive power supplied from the feeder 5 to the train 4 is large. Therefore, when the train 4 brakes, power is supplied from the train 4 to the charging station 6, when the train 4 is stopped, power is supplied from the feeding substation 2 to the charging station 6, and when the train 4 is powering, the supply of power from the feeder 5 to the charging station 6 is stopped.

[0044] During time period T2 when the positive power supplied to the train 4 from the feeder 5 is large, the power management device 50 suppresses the power P5 supplied from the feeder 5 to the private line 9, so that the power P2 supplied from the main substation 1 to the feeding substation 2 is kept at or below the rated capacity Pn2, while a large amount of power P6 exceeding the rated capacity Pn2 can be supplied to the charging station 6 via the private line 9. This makes it possible to increase the number of electric vehicles 600 that can be charged without having to perform equipment upgrades that increase the rated capacities of the main substation 1 and the feeding substation 2.

[0045] The operational flow of electric vehicle charging system 300 according to the second embodiment is the same as the operational flow of electric vehicle charging system 300 according to the first embodiment shown in FIG. 6 , except that in step S2, substation available capacity prediction unit 523 calculates the available capacity of feeding substation 2 instead of the available capacity of main substation 1. In addition, in step S3, table creation unit 524 creates a charging rate table by setting a high charging fee for a time period when the available capacity of feeding substation 2 is small and the maximum charging power is small because the train 4 is powering and the power P2 supplied to feeding substation 2 is large, in order to avoid a concentration of charging demand during that time period. In this way, by setting a variable charging fee that differs for each time period based on the maximum charging power based on the available capacity of feeding substation 2, the solar-generated power P7, and the predicted value of regenerative power, optimization of the charging plan for electric vehicle 600 is promoted.

[0046] The electric vehicle charging system 300 according to the second embodiment predicts the power consumption of the train 4 connected to the feeder line 5 when it is powering, the regenerative power generated when the train 4 is braking, and the available capacity of the feeding substation 2 for each time period, and controls the power converter 8 based on the prediction so that the power supplied to the feeding substation 2 does not exceed a preset rated capacity. This makes it possible to increase the number of electric vehicles 600 that can be charged without having to perform equipment updates that increase the rated capacity of the feeding substation 2.

[0047] Embodiment 3 9 is a diagram showing the configuration of an electric vehicle charging system according to embodiment 3. Only the parts that differ from electric vehicle charging system 300 according to embodiment 2 will be described, and a description of the parts in common will be omitted.

[0048] As with electric vehicle charging system 300 according to embodiment 2, in electric vehicle charging system 300 according to embodiment 3, the current flowing in private line 9 is direct current. In electric vehicle charging system 300 according to embodiment 3, feeding substation equipment 2 includes power converter 203 that steps down the DC power output from rectifier 202. Feeding substation equipment 2 supplies DC power stepped down by transformer 201 to private line 9, and supplies DC power stepped down by power converter 203 to feeder line 5. When regenerative power generated when train 4 brakes is recovered by feeder line 5, the regenerative power is boosted by power converter 8, and power P5 is supplied from feeder line 5 to private line 9. Solar power generation equipment 7 is installed in charging station 6.

[0049] FIG. 10 is a diagram showing an example of power generated in the electric vehicle charging system according to the third embodiment. In FIG. 10, the vertical axis represents power, and the horizontal axis represents time. Power P2 is power supplied to the feeding substation 2. Power P4 is power exchanged between the train 4 and the feeder 5. Power P6 is power supplied to the charging station 6.

[0050] Time period T1 is a time period when train 4 is stopped, and the positive power P4 supplied to train 4 from feeder 5 is small. Time period T2 is a time period when train 4 is powering, and the positive power P4 supplied to train 4 from feeder 5 is large. Time period T3 is a time period when train 4 is coasting, and the positive power P4 supplied to train 4 from feeder 5 is small. Time period T4 is a time period when train 4 is braking, and negative power is supplied from train 4 to feeder 5.

[0051] The power management device 50 controls the charger 601, the storage battery 602, the power converter 603, the power converter 604, the power converter 8, and the power converter 203 to supply power P6 from the private line 9 to the charging station 6 during time periods T1 and T3 when the positive power supplied from the feeder 5 to the train 4 is small and during time period T4 when negative power is supplied from the train 4 to the feeder 5, and to suppress the supply of power P6 from the private line 9 to the charging station 6 during time period T2 when the positive power supplied from the feeder 5 to the train 4 is large. That is, during time periods T1, T3, and T4, the power management device 50 supplies power from the feeder 5 to the private line 9 via the power converter 8, and supplies power from the private line 9 to the charging station 6 via the power converter 603. On the other hand, during time period T2, the power management device 50 suppresses at least one of the supply of power P5 from the feeder line 5 to the private line 9 via the power converter 8 and the supply of power P6 from the private line 9 via the power converter 603.

[0052] During time period T2 when the positive power supplied to train 4 from feeder line 5 is large, power management device 50 suppresses power P6 supplied from private line 9 to charging station 6, thereby making it possible to keep power P2 supplied from main substation 1 to feeding substation 2 at or below rated capacity Pn2, while supplying large power P6 exceeding rated capacity Pn2 to charging station 6 via private line 9. This makes it possible to increase the number of electric vehicles 600 that can be charged without upgrading the main substation 1 and feeding substation 2 to increase their rated capacities.

[0053] The operational flow of electric vehicle charging system 300 according to the third embodiment is the same as the operational flow of electric vehicle charging system 300 according to the first embodiment shown in FIG. 6 , except that in step S2, substation available capacity prediction unit 523 calculates the available capacity of feeding substation 2 instead of the available capacity of main substation 1. Also, in step S3, during a time period when the available capacity of feeding substation 2 is small and the maximum charging power is small because the train 4 is powering and the power P2 supplied to feeding substation 2 is large, a high charging fee is set to avoid a concentration of charging demand during that time period. In this way, by setting a variable charging fee that differs for each time period based on the maximum charging power based on the available capacity of feeding substation 2, the solar-generated power P7, and the predicted value of regenerative power, optimization of the charging plan for electric vehicle 600 is promoted.

[0054] The electric vehicle charging system 300 according to the third embodiment predicts the power consumption of the train 4 connected to the feeder line 5 when it is powering, the regenerative power generated when the train 4 is braking, and the available capacity of the feeding substation 2 for each time period, and based on the predictions, controls the power converter 603 so that the power supplied to the feeding substation 2 does not exceed a preset rated capacity. This makes it possible to increase the number of electric vehicles 600 that can be charged without having to perform equipment updates that increase the rated capacity of the feeding substation 2.

[0055] Next, the hardware configurations of the power management device 50 and electric vehicle operation management device 60 that make up the electric vehicle charging system 300 will be described. FIG. 11 is a diagram showing an example of the hardware configuration of a power management device of an electric vehicle charging system according to any one of Embodiments 1 to 3. As shown in FIG. 11, the power management device 50 is a computer system including a processor 101, a memory 102, a storage device 103, and an interface circuit 104. The processor 101, the memory 102, the storage device 103, and the interface circuit 104 can transmit and receive data to and from each other via a bus 105.

[0056] The processor 101 executes the functions of the control unit 51 and the processing unit 52 by reading and executing an operating system (OS) and processing programs stored in the storage device 103. Note that part or all of the control unit 51 and the processing unit 52 may be configured with hardware such as an ASIC (Application Specific Integrated Circuit) and an FPGA (Field Programmable Gate Array). In other words, the processing circuitry that realizes part or all of the control unit 51 and the processing unit 52 may be dedicated hardware.

[0057] The processor 101 can also read the OS and processing program from one or more storage media including a magnetic disk, a USB (Universal Serial Bus) memory, an optical disk, a compact disk, and a DVD (Digital Versatile Disc) via an interface not shown, store them in the storage device 103, and execute them.

[0058] Furthermore, the power management apparatus 50 may be realized by a plurality of information processing devices connected to each other. When the power management apparatus 50 includes a plurality of information processing devices, the processes executed by the power management apparatus 50 can be regarded as a single virtual information processing device by each of the plurality of information processing devices executing the processes.

[0059] Similarly, the electric vehicle operation management device 60 is a computer system including a processor 101, a memory 102, a storage device 103, and an interface circuit 104. The processor 101 executes the functions of the control unit 61 and the processing unit 62 by reading and executing an OS and a processing program stored in the storage device 103. Note that part or all of the control unit 61 and the processing unit 62 may be configured with hardware such as an ASIC and an FPGA. In other words, the processing circuit that realizes part or all of the control unit 61 and the processing unit 62 may be dedicated hardware.

[0060] The configurations shown in the above embodiments are merely examples of the content, and may be combined with other known technologies, or parts of the configurations may be omitted or modified without departing from the spirit of the invention. [Explanation of symbols]

[0061] 1 Main substation equipment, 2 Feeder substation equipment, 3 Private line substation equipment, 4 Train, 5 Feeder line, 6 Charging station, 7 Solar power generation equipment, 8,203,603,604,701 Power converter, 9 Private line, 50 Power management device, 51,61 Control unit, 52,62 Processing unit, 60 Electric vehicle operation management device, 101 Processor, 102 Memory, 103 Storage device, 104 Interface circuit, 105 Bus, 201 Transformer, 202 Rectifier, 300 Electric vehicle charging system, 521 Solar power generation amount prediction unit, 522 Regenerative power amount prediction unit, 523 Substation equipment available capacity prediction unit, 524 Table creation unit, 600 Electric vehicle, 601 Charger, 602 Storage battery, 621 Charging demand prediction unit, 622 Charging plan creation unit.

Claims

1. a charging station equipped with a charger capable of charging an electric vehicle using power supplied from a private line; a substation facility for supplying power to the private power lines and the feeder lines; a power converter installed between the feeder line and the private line, which reduces the voltage of power supplied from the feeder line to the private line; a power management device that manages power supplied to the charging station by controlling the substation and the power converter, the power management device predicts, for each time period, the power used by the train connected to the feeder line when it is powered, the regenerative power generated when the train is braking, and the available capacity of the substation equipment; An electric vehicle charging system characterized by controlling the substation and the power converter based on the prediction so that the power supplied to the substation does not exceed a preset rated capacity.

2. 2. The electric vehicle charging system according to claim 1, wherein the power management device supplies power from the feeder to the private line and from the private line to the charging station when the train connected to the feeder is stopped, coasting, or braking, and suppresses at least one of the supply of power from the feeder to the private line and the supply of power from the private line to the charging station when the train is powering.

3. 3. The electric vehicle charging system according to claim 1, wherein the substation equipment includes a main substation equipment that steps down the voltage of the electric power supplied from the power grid and outputs the power, and a power feeding substation equipment that steps down the voltage of the electric power supplied from the main substation equipment and converts the power to DC.

4. Equipped with a solar power generation facility that generates solar power, The solar power generation facility is connected to the private line, 4. The electric vehicle charging system according to claim 3, wherein the power management device reduces the power supplied from the feeding substation to the feeder line by an amount corresponding to the solar-generated power and the regenerated power during the time periods when the solar-generated power is supplied to the private line and the time periods when the regenerated power is generated.

5. 5. The electric vehicle charging system according to claim 4, wherein the power management device predicts the time periods in which the regenerative power will be generated and the amount of power of the regenerative power based on the train operation information, and changes the amount of power supplied from the main substation to the feeding substation when the train brakes for each time period based on the prediction results.

6. a private line substation that supplies the power supplied from the main substation to a private line connected to the charging station; 4. The electric vehicle charging system according to claim 3, wherein the power management device changes the power supplied from the main substation to the private line substation when the train is powering and when the train is stopped, coasting, or braking, so that the sum of the power supplied from the main substation to the feeding substation and the power supplied from the main substation to the private line substation is equal to or less than the rated capacity of the main substation.

7. Equipped with a solar power generation facility that generates solar power, The solar power generation facility is connected to the private line, 7. The electric vehicle charging system of claim 6, wherein the power management device reduces the power supplied from the private line substation to the private line by the amount of the solar-generated power and the regenerated power during the time periods when the solar-generated power is supplied to the private line and the time periods when the regenerated power is generated.

8. 8. The electric vehicle charging system according to claim 7, wherein the power management device predicts the time periods in which the regenerative power will be generated and the amount of the regenerative power based on the train operation information, and changes the amount of power supplied from the main substation to the private line substation when the train brakes, for each time period, based on the prediction results.

9. an electric vehicle operation management device that manages the operation schedule of the electric vehicle; the power management device transmits a charging fee table created by setting a charging fee for the electric vehicle for each time period according to the amount of generated regenerative power to the electric vehicle operation management device; 5. The electric vehicle charging system according to claim 4, wherein the electric vehicle operation management device determines a time period during which the electric vehicle is to be charged based on the charging fee table.

10. 10. The electric vehicle charging system according to claim 9, wherein the power management device creates the charging fee table by setting a lower charging fee for the electric vehicle during time periods when the amount of regenerative power generated is greater and during time periods when the amount of solar-generated power is greater.

11. In an electric vehicle charging system including a charging station equipped with a charger capable of charging an electric vehicle using power supplied from a private line, a substation that supplies power to the private line and a feeder line, and a power converter that is installed between the feeder line and the private line and that reduces the voltage of the power supplied from the feeder line to the private line, a power management device that manages power supplied to the charging station by controlling the substation equipment and the power converter, A power management device characterized by predicting the power usage of a train connected to the feeder line when powering, the regenerative power generated when the train brakes, and the available capacity of the substation equipment for each time period, and controlling the substation equipment and the power converter based on the predictions so that the power supplied to the substation equipment does not exceed a preset rated capacity.

12. An electric vehicle charging method using an electric vehicle charging system including: a charging station equipped with a charger for charging an electric vehicle using power supplied from a private line; a substation that supplies power to the private line and a feeder; a power converter that is installed between the feeder and the private line and that steps down the power supplied from the feeder to the private line; and a power management device that manages power supplied to the charging station by controlling the substation and the power converter, the power management device predicts, for each time period, the power consumption used by the train connected to the feeder line when the train is powered, the regenerative power generated when the train is braking, and the available capacity of the substation equipment; and controlling the substation and the power converter based on the prediction so that the power supplied to the substation does not exceed a preset rated capacity.

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