Power supply device

Abstract

To provide a power supply device which can contribute to reduction of a discharge amount of carbon dioxide at low cost.SOLUTION: A power supply device connected to a substation which converts AC into DC and outputs DC, and to a feeding circuit connected to an electric vehicle which serves as a load includes: a first power converter which is connected to the feeding circuit and converts voltage of the feeding circuit into arbitrary voltage; a first storage battery which is connected to the first power converter and is connected to one or both of a solar panel and an electric vehicle charger; and a control unit for controlling the first power converter and the first storage battery so that power which the solar panel generates is supplied to the electric vehicle charger or the first storage battery. The electric vehicle charger charges the electric vehicle connected to the electric vehicle charger by using at lest one of power which the solar panel generates and power discharged from the first storage battery.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to a power supply device. [Background technology]

[0002] There is a growing demand for resilience in social infrastructure facilities in terms of storm and flood damage such as typhoons, earthquakes, and energy security. In addition, the global trend toward decarbonization is calling for transportation systems to move away from fossil fuels and to further conserve energy. In electric railways, the application of battery technology has led to the storage of surplus regenerative power in batteries, which is the energy that has been consumed as heat by mechanical brakes, and the technology to reuse it when accelerating.

[0003] In addition, the shift to electric vehicles is progressing rapidly. Buses that were previously powered by diesel engines are now being operated as electric buses. Furthermore, EV buses are now being operated so that they can use natural energy, such as solar and wind power, which are considered clean power sources, to charge the onboard storage batteries and use the energy while traveling.

[0004] For example, Patent Document 1 shows that a converter for charging an electric vehicle, a storage battery, a solar power generation system, and an inverter for AC grid connection are connected through a DC bus, and that the storage battery and the grid connection inverter complement solar power generation, which is an unstable natural energy source.

[0005] Patent Document 2 describes how installing storage batteries at stations will ensure emergency power sources and contribute to the infrastructure resilience of the railway system.

[0006] Non-Patent Document 1 describes connecting a large-scale photovoltaic power generation system to an AC system to which a substation is connected, and using the system in a railway system via a rectifier in a DC substation and a DC feeder line.

[0007] Furthermore, Non-Patent Document 2 describes how installing storage batteries in stations will ensure emergency power sources and contribute to the infrastructure resilience of railway systems. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2022 / 004611 [Patent Document 2] JP 2022-112553 A [Non-patent literature]

[0009] [Non-Patent Document 1] 2022 IEEJ Industrial Applications Conference Tracking PV output characteristics of railway demand using large-scale energy storage devices connected to DC feeding circuits [Non-Patent Document 2] 2022 IEEJ Industrial Applications Conference Evaluation of useful regenerative energy from an EV charging system connected to a DC electric railway Summary of the Invention [Problem to be solved by the invention]

[0010] The technique disclosed in Patent Document 1 has a problem in that when charging a large number of electric vehicles or charging high-power electric vehicles, a large-scale charging power supply system needs to be constructed.

[0011] The technology disclosed in Patent Document 2 has the problem that when backing up a large facility such as a station or operating it as an evacuation shelter in an emergency, the required battery capacity increases, leading to increased costs.

[0012] In the technology disclosed in Non-Patent Document 1, injecting the power generated by one large-scale photovoltaic power generation from each DC substation through a power receiving system requires the construction and maintenance of a new power receiving system, which is problematic in that it tends to be costly. In addition, when injecting the power from the photovoltaic power generation into the power feeding system via a rectifier, if regeneration occurs in the train, the overhead line voltage rises, and if it becomes higher than the no-load sending voltage of the rectifier, the rectifier diode is reverse blocked, making it impossible to inject energy into the power feeding system.

[0013] In the technology disclosed in Non-Patent Document 2, the overhead line voltage fluctuates significantly depending on the installation location or the state of the power supply equipment. Therefore, if EV charging is performed according to the overhead line voltage, there is a problem that it is not possible to achieve the target charging of the EV within the desired time.

[0014] The present invention has been made in light of the above circumstances, and has an object to provide a power supply device that can contribute to reducing carbon dioxide emissions at low cost. [Means for solving the problem]

[0015] In one embodiment, a power supply device connected to a substation that converts AC to DC and outputs it, and to a feeding circuit that is connected to an electric vehicle that serves as a load, includes a first power converter connected to the feeding circuit and converts the voltage of the feeding circuit into an arbitrary voltage, a first storage battery connected to the first power converter and connected to a solar panel and one or both of an electric vehicle charger, and a control unit that controls the first power converter and the first storage battery so that power generated by the solar panel is supplied to the electric vehicle charger or the first storage battery, and the electric vehicle charger charges an electric vehicle connected to the electric vehicle charger using at least one of the power generated by the solar panel and the power discharged from the first storage battery. [Brief description of the drawings]

[0016] [Figure 1]FIG. 1 is a schematic configuration diagram of a power supply system including a circuit diagram of a power supply device according to a first embodiment. [Diagram 2] FIG. 2 is a diagram showing an example of control of the charge / discharge converter and the first storage battery by the control unit. [Diagram 3] FIG. 3 is a schematic configuration diagram of a power supply system including a circuit diagram of a power supply device according to the second embodiment. [Figure 4] FIG. 4 is a schematic configuration diagram of a power supply system including a circuit diagram of a power supply device according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The power supply system will be described in detail below with reference to the drawings. In the following embodiments, parts with the same numbers perform the same operations, and redundant description will be omitted.

[0018] [First embodiment] (composition) FIG. 1 is a schematic configuration diagram of a power supply system including a circuit diagram of a power supply device according to a first embodiment. As shown in FIG. 1, the power supply system according to the first embodiment includes a substation 2, a feeder / overhead line / third rail 3, a rail 4, a train 30, a third contactor 22, a second transformer 24, a power supply device 7 arranged inside or outside a building 5, a load 25 including an air conditioner and a DC power supply device 26 arranged inside the building 5, and an electric vehicle 16.

[0019] One side of the substation 2 is connected to the AC system 1-1, and the other side is connected to the feeder, overhead line, third rail 3, and rail 4. Here, the AC system 1-1 is connected to another substation 2 not shown in FIG. 1 or to a general power company. The substation 2 is a substation 2 that supplies power to the feeding circuit. When the feeding method is DC, the substation 2 converts AC to DC, and when the feeding method is AC, the substation 2 converts it to single-phase AC of any voltage. The feeder, overhead line, third rail 3, and rail 4 form a feeding circuit.

[0020] The feeder line / overhead line / third rail 3 and the rail 4 are connected to a power supply unit 7 and a train 30. The train 30 functions as a load for the feeder circuit. Here, the train 30 may be a general electric car.

[0021] The third contactor 22 has one end connected to the AC system 1-2 and the other end connected to the second transformer 24. Here, the AC system 1-2 is connected to a general power company. That is, the AC system 1-2 forms a commercial AC power path. In addition, the second transformer 24 is connected to the power supply device 7.

[0022] The building 5 is arranged, for example, along a railway line, in a station building, etc. The building 5 may be a container or a cubicle.

[0023] The power supply device 7 includes a power feeding contactor 6, a charge / discharge converter 8, a first storage battery 9, an inverter 11, a solar panel 13, a first DC / DC converter 14, an electric vehicle charger 15, a first transformer 18, a first AC contactor 20, a second AC contactor 21, a fourth AC contactor 23, and a DC contactor 28. The solar panel 13 and the electric vehicle charger 15 are installed outside the building 5, and the rest are installed inside the building 5.

[0024] The power feeding contactor 6 is disposed between the power feeding line / overhead line / third rail 3 and the charge / discharge converter 8. When the power feeding contactor 6 is closed, it secures the connection of the power feeding circuit with the power supply 7, and when it is released, it separates the connection between the power supply 7 and the power circuit.

[0025] The charge / discharge converter 8 operates as a first converter used to charge the first storage battery 9 with power from the feeding power circuit or to discharge the power of the first storage battery 9 to the feeding power circuit. For example, when the feeding circuit is AC, the charge / discharge converter 8 serving as the first converter is an AC / DC inverter, and when the feeding circuit is DC, the charge / discharge converter 8 serving as the first converter is a DC / DC converter.

[0026] The first storage battery 9 includes, for example, cells connected in series. Here, each cell may be, for example, a general lithium-ion battery using lithium titanate as the negative electrode. The first storage battery 9 is not limited to one, and may be configured by connecting a plurality of first storage batteries 9 in series or in parallel. The first storage battery 9 may be a storage battery unit in which a control device for monitoring the temperature, voltage, and current of the first storage battery 9, and a fuse and a contactor are inserted in series with the first storage battery 9. The first storage battery 9 is neutral-grounded.

[0027] In the first embodiment, the first storage battery 9 is connected to the inverter 11, the first DC / DC converter 14, and the electric vehicle charger 15, respectively.

[0028] The inverter 11 converts the DC voltage discharged from the first storage battery 9 into an arbitrary AC voltage, and outputs the AC voltage to an inverter AC output system 17 between the inverter 11 and a first transformer 18 .

[0029] The inverter AC output system 17 is connected to a transformer secondary side AC system 19 via a first transformer 18. The transformer secondary side AC system 19 is connected to a load 25 including an air conditioner and a DC power supply device 26 via a first AC contactor 20 and a second AC contactor 21. That is, the power of the first storage battery 9 is supplied to the load 25 including an air conditioner and the DC power supply device 26 via the inverter 11, the first transformer 18, the first AC contactor 20, and the second AC contactor 21. Furthermore, the inverter AC output system 17 is connected to a commercial AC circuit, which is the AC system 1-2, via the first AC contactor 20, the fourth AC contactor 23, the second transformer 24, and the third contactor 22.

[0030] When both the first AC contactor 20 and the second AC contactor 21 are turned on, the connection between the load 25 including the air conditioner and the DC power supply 26 and the power supply 7 is secured. On the other hand, when at least one of the first AC contactor 20 and the second AC contactor 21 is opened, the connection between the load 25 including the air conditioner and the DC power supply 26 and the power supply 7 is disconnected.

[0031] When both the first AC contactor 20 and the fourth AC contactor 23 are closed, the connection with the AC system 1-2 is secured. On the other hand, when at least one of the first AC contactor 20 and the fourth AC contactor 23 is released, the connection between the AC system 1-2 and the power supply device 7 is disconnected.

[0032] The load 25 including an air conditioner has the function of cooling the heat generated by the power supply device 7 within the building 5.

[0033] The DC power supply device 26 converts the AC voltage from the first transformer 18 into a DC voltage, and supplies the control voltage (e.g., 100 V) required for the control power supply to the charge / discharge converter 8 and the first storage battery 9 via a DC power supply path 27.

[0034] The first DC / DC converter 14 is connected to the solar panel 13. The first DC / DC converter 14 is used to convert the power (voltage) generated by the solar panel 13 into a voltage used in the first storage battery 9.

[0035] The electric vehicle charger 15 is connected to the electric vehicle 16. The electric vehicle charger 15 is used to convert the voltage used in the first storage battery 9 and the voltage generated by the solar panel 13, which is converted by the first DC / DC converter 14, into a voltage that can be charged to the electric vehicle 16. Here, the electric vehicle 16 is not limited to a pure electric vehicle 16 that runs only on battery energy, and may be a vehicle equipped with a storage battery for driving the vehicle, such as a plug-in hybrid vehicle.

[0036] The DC contactor 28 is connected between the first storage battery 9 and the inverter 11, the first DC / DC converter 14, and the electric vehicle charger 15, and is used to isolate the first storage battery 9 from the inverter 11, the first DC / DC converter 14, and the electric vehicle charger 15.

[0037] The control unit 29 performs opening and closing operations and detection of the opening and closing states of the power supply contactor 6, the first AC contactor 20, the fourth AC contactor 23, and the DC contactor 28. The control unit 29 also performs charge and discharge control of the charge and discharge converter 8, detection of the state of charge (SOC), temperature, voltage, etc. of the first storage battery 9, and, if the first storage battery 9 is a power storage unit, opening and closing operations of the built-in contactors. Furthermore, the control unit 29 controls the inverter 11, the first DC / DC converter 14, and the electric vehicle charger 15. Note that the control unit 29 does not need to be integrated into one control unit, and may be realized by, for example, mounting a control unit 29 in each of the charge and discharge converter 8, the inverter 11, the first DC / DC converter 14, and the electric vehicle charger 15, and linking the respective control units 29 through communication.

[0038] Here, in the example of FIG. 1, an example is shown in which the solar panel 13 and the electric vehicle charger 15 are connected to the first storage battery, but it goes without saying that the power supply device 7 may include only one of them.

[0039] (Control Action) Next, an example of the control operation of the power supply device 7 will be described with reference to Fig. 1. For example, assume that the fourth AC contactor 23 is released, and the power feeding contactor 6, the first AC contactor 20, the second AC contactor 21, and the DC contactor 28 are in an on state. At this time, the control unit 29 controls the inverter 11 at a constant voltage so as to keep the voltage of the inverter AC output system 17 or the transformer secondary side AC system 19 connected to the inverter 11 at a constant AC voltage.

[0040] Furthermore, the first DC / DC converter 14 performs maximum power point tracking control (MPPT) so as to maximize the power generated by the solar panel 13. The electric vehicle charger 15 supplies the electric vehicle 16 with the power required for charging the electric vehicle 16. The charge / discharge converter 8 performs a discharge or charge operation on the feeding circuit according to the overhead line voltage. For example, when the feeding voltage rises, the first storage battery 9 is charged, and when the feeding voltage drops, the first storage battery 9 is discharged. The charge / discharge converter 8 also performs control so that the higher the SOC of the first storage battery 9, the higher the feeding voltage at which charging from the feeding circuit to the first storage battery 9 starts, and the higher the feeding voltage at which discharging from the first storage battery 9 starts to the feeding circuit.

[0041] FIG. 2 is a diagram showing an example of control of the charge / discharge converter 8 and the first storage battery 9 by the control unit 29. As shown in FIG.

[0042] 2, when the SOC becomes high, the control unit 29 controls the charge / discharge converter 8 to increase the charge threshold voltage at which charging of the first storage battery 9 starts. Similarly, when the SOC becomes high, the control unit 29 controls the charge / discharge converter 8 to increase the discharge threshold voltage at which discharging from the first storage battery 9 to the power feeding circuit starts.

[0043] Conversely, the control unit 29 controls the charge / discharge converter 8 to lower the charge threshold voltage at which charging starts to the first storage battery 9 as the SOC decreases. Similarly, the control unit 29 controls the charge / discharge converter 8 to lower the discharge threshold voltage at which discharging starts from the first storage battery 9 to the power feeding circuit as the SOC decreases.

[0044] Next, the control in the state where the fourth AC contactor 23 is turned on will be described. At this time, the inverter 11 performs current control on the inverter AC output system 17. This current control is calculated in the control unit 29, and the current is controlled so that a target active power is output. The target active power is provided, for example, as a table in the control unit 29, and the control unit 29 controls so that the active power command value increases as the SOC of the first storage battery 9 increases. This allows the control unit 29 to prevent the SOC of the first storage battery 9 from becoming fully charged or overcharged. Conversely, the control unit 29 controls so that the active power command value decreases as the SOC of the first storage battery 9 decreases. This allows the control unit 29 to prevent overdischarge of the first storage battery 9.

[0045] Next, the control when the solar panel 13 generates power and the electric vehicle 16 is charged will be described. When the amount of power generated by the solar panel 13 exceeds the power required to charge the electric vehicle 16, the control unit 29 controls the system so that the power required to charge the electric vehicle 16 is supplied from the power generated by the solar panel 13, and the remaining power is charged to the first storage battery 9.

[0046] On the other hand, when the amount of power generated by the solar panel 13 is less than the power required for charging the electric vehicle 16, the control unit 29 controls the electric vehicle 16 to receive the power generated by the solar panel 13, and further controls the first storage battery 9 to supply the electric vehicle 16 via the electric vehicle charger 15 with the power obtained by subtracting the amount of power generated by the solar panel 13 from the power required for charging the electric vehicle 16. By charging in this manner, the electric vehicle 16 can be charged without placing a large load on the AC system 1-1 and the AC system 1-2. Furthermore, by providing the first storage battery 9 in this manner, it is not necessary to construct a new power receiving system and power receiving equipment, which contributes to reducing costs. Furthermore, in the first embodiment, when the amount of power generated by the electric vehicle 16 exceeds the amount of power generated by the solar panel 13, power is supplied from the first storage battery 9 charged by the power supply circuit. This makes it possible to charge the electric vehicle 16 without being restricted by the range of the overhead line voltage. This can be realized by changing the overhead line voltage threshold at which the charge / discharge converter 8 starts charging and the overhead line voltage threshold at which it starts discharging according to the state of charge of the first storage battery 9. For example, even if charging of the electric vehicle 16 continues in a state where the state of charge of the first storage battery 9 has decreased, i.e., the SOC has decreased, the voltage at which charging and discharging start decreases, so that it is possible to prevent the first storage battery 9 from being over-discharged.

[0047] Furthermore, when the power generated by the solar panel 13 exceeds the power required to charge the electric vehicle 16, or when the electric vehicle 16 is not connected to the electric vehicle charger 15, the power generated by the solar panel 13 is charged to the first storage battery 9. Then, when it is necessary to discharge the power to the power feeding circuit, the power is discharged from the first storage battery 9 to the power feeding circuit.

[0048] Of course, the power generated by the solar panel 13 may be supplied to a load 25 including an air conditioner and a DC power supply device 26 via the inverter 11 and the first transformer 18.

[0049] Next, the operation when the power generated by the solar panel is used in the power supply circuit will be described.

[0050] In general, the load power of the power feeding circuit fluctuates greatly when the electric train 30 accelerates or decelerates. A high-output load is generated in the power feeding circuit during a short period of time when the electric train 30 accelerates. In such a case, the current in the power feeding circuit increases, and power feeding loss due to resistance in the power feeding circuit is likely to occur.

[0051] For example, when a current twice as large as usual flows through the feeding circuit, the resistance loss is four times as large as the normal resistance loss, and when a current four times as large as usual flows through the feeding circuit, the resistance loss is sixteen times as large as the normal resistance loss. Therefore, it is desirable to control the discharge from the first storage battery 9 to the feeding circuit via the charge / discharge converter 8 so that the output is high when the feeding circuit is under high load. As described above, the power generated by the solar panel 13 is temporarily charged into the first storage battery 9. Then, when the feeding circuit is under high load, the first storage battery 9 discharges the power at high output to the feeding circuit. This contributes to reducing the feeding loss. In addition, since the power generated by the solar panel 13 can be directly discharged to the feeding circuit via the first storage battery 9, it contributes to reducing the carbon dioxide emissions of the railway system.

[0052] Furthermore, when the AC system 1-2 experiences a power outage, the first storage battery 9 can supply power to the load 25 including the air conditioning on the AC side and the DC power supply device 26 via the inverter 11. In this case, if the first storage battery 9 is in a state in which it can receive power from the power supply circuit, i.e., the AC system 1-1, the first storage battery 9 receives power from the AC system 1-1 side. Then, the first storage battery 9 can supply the received power to the load 25 including the air conditioning and the DC power supply device 26 via the inverter 11.

[0053] In addition, when the power (AC power) from the electric power company to the AC system 1-1 and the AC system 1-2 is cut off and the AC system 1-1 can receive power from a distant substation 2, the voltage drops when the electric vehicle 16 is charged directly from the power supply circuit without going through the first storage battery 9. Therefore, it is possible to charge the first storage battery 9 with a small amount of power, and discharge the charged first storage battery 9 to the electric vehicle 16 with a large amount of power via the electric vehicle charger 15. For example, when the electric vehicle 16 is an electric route bus that requires a large amount of power for charging, even if the power from the electric power company to the AC system 1-1 and the AC system 1-2 is cut off, the electric route bus can continue to operate as a part of the public transportation system. Therefore, the power supply device 7 also contributes to improving infrastructure resilience.

[0054] (Effects of the first embodiment) According to the first embodiment described above, by providing the power supply device 7 equipped with the charge / discharge converter 8 and the first storage battery 9 connected to the feeding circuit and the solar panel 13, it is possible to supply the power generated by the solar panel 13 to the feeding circuit when the feeding circuit is under high load. This can contribute to reducing carbon dioxide emissions from the railway system.

[0055] Moreover, according to the first embodiment, the control unit 29 changes a threshold value for starting charging / discharging the first storage battery 9 by the feeding circuit via the charge / discharge converter 8 in accordance with the SOC of the first storage battery 9. This makes it possible to prevent the first storage battery 9 from being over-discharged even if the electric vehicle 16 is charged in a state in which the SOC of the first storage battery 9 is low. Furthermore, by using the first storage battery 9, a large load is not applied to the AC system 1-1 and the AC system 1-2 when the electric vehicle 16 is being charged. This eliminates the need to build a new power receiving system and power receiving equipment, which contributes to cost reduction.

[0056] Furthermore, even if power from the power company to the AC systems 1-1 and 1-2 is interrupted, the power supply device 7 can receive power from the distant substation 2 connected to the AC system 1-1. Then, the first storage battery 9 stores the power from the distant substation 2, and the stored power can be used to charge the electric vehicle 16. This allows the power supply device 7 to contribute to improving infrastructure resilience in the public transportation system.

[0057] [Second embodiment] FIG. 3 is a schematic configuration diagram of a power supply system including a circuit diagram of a power supply device 7 according to the second embodiment. The second embodiment differs from the first embodiment in that the first storage battery 9 is connected to a second DC / DC converter 10 via a DC contactor 28, and a second storage battery 12 is connected between the second DC / DC converter 10 and the inverter 11. In addition, the second DC / DC converter 10 and the second storage battery 12 are controlled by a control unit 29.

[0058] The second DC / DC converter 10 may be an insulating transformer having a built-in transformer. For example, the second DC / DC converter 10 may be a dual active bridge circuit, a circuit in which a chopper and a resonant high-frequency insulating circuit are combined, or the like.

[0059] The second storage battery 12 may be arranged so as to be directly connected to the second DC / DC converter 10. The second storage battery 12 may be a storage battery unit having a built-in DC / DC converter as a second power converter and connected to the second DC / DC converter 10.

[0060] The control unit 29 controls the above-mentioned second power converter in accordance with the charging rate of the second storage battery 12. For example, when increasing the charging rate of the second storage battery 12, the control unit 29 controls so that power from the circuit in which the first storage battery 9 is installed is supplied to the second storage battery 12 side via the second power converter. Conversely, when the charging rate of the second storage battery 12 is high, the control unit 29 supplies power from the second storage battery 12 to the DC circuit side in which the first storage battery 9 is installed.

[0061] By installing the second DC / DC converter 10, it is possible to suppress voltage fluctuations when power is supplied from the first storage battery 9 to other devices. In addition, the second DC / DC converter 10 can step down the voltage from the first storage battery 9 to a DC voltage appropriate for the inverter 11, the second storage battery 12, the first DC / DC converter 14, and the electric vehicle charger 15, for example. For example, when the voltage input from the first storage battery 9 to the second DC / DC converter 10 is 1500V, the second DC / DC converter 10 can make the output of the second DC / DC converter 10 200V. In this way, it is possible to configure the power supply device 7 by combining inexpensive converters (for example, existing converters) without developing these devices separately. This can reduce the manufacturing cost of the power supply device 7.

[0062] In the second embodiment, the same operations as those in the first embodiment described above can be performed, but the description thereof will be omitted here to avoid duplication.

[0063] (Effects of the second embodiment) According to the second embodiment described above, by installing the second DC / DC converter 10, it is possible to convert the DC voltage from the first storage battery 9 into a DC voltage appropriate for the inverter 11, the second storage battery 12, the first DC / DC converter 14, and the electric vehicle charger 15. This makes it possible to configure the power supply device 7 by combining these devices at low cost. This allows the manufacturing cost of the power supply device 7 to be reduced.

[0064] [Third embodiment] FIG. 4 is a schematic configuration diagram of a power supply system including a circuit diagram of a power supply device 7 according to the third embodiment. In the third embodiment, a fifth AC contactor 31 is connected to the AC output of the inverter 11. The fifth AC contactor 31 is connected to a first AC contactor 20 via a first transformer 18. The first AC contactor 20 is connected to a second storage battery 12 and an electric vehicle charger 15. The first AC contactor 20 is further connected to a solar panel 13 via a power conditioner 32.

[0065] Therefore, the third embodiment differs from the first embodiment in that a fifth AC contactor 31 is arranged at the AC output of the inverter 11, and a second storage battery 12, a power conditioner 32, and an electric vehicle charger 15 are connected to the AC side.

[0066] The power conditioner 32 may be configured with only an inverter, or may be configured with a combination of an inverter and a DC / DC converter and connected to the solar panel 13.

[0067] In this way, in the third embodiment, the power generated by the solar panel 13 is received on the AC path side and charged into the first storage battery 9 on the DC system side. Furthermore, in the third embodiment, the electric vehicle 16 is charged on the AC path side. In this way, the electric vehicle 16 can receive power from the AC system 1-2, and the use of the power supply device 7 in public transportation infrastructure such as electric route buses contributes to redundancy of the charging power source.

[0068] In addition, by arranging the second storage battery 12, the power conditioner 32, and the electric vehicle charger 15 on the AC side, these devices can be configured from general consumer products. This eliminates the need to develop these devices exclusively, making it possible to reduce the manufacturing costs of the power supply device 7.

[0069] Also, the second storage battery 12 is connected to the inverter 11 on the AC side. Therefore, when the fourth AC contactor 23 is opened, the voltage required in the transformer secondary side AC system 19 may be generated by the power of the second storage battery 12 in addition to the power of the first storage battery 9 via the inverter 11. In this case, the inverter 11 operates in an interconnected manner on the AC side generated by the second storage battery 12 and the inverter 11. At this time, the operation of the active power of the inverter 11 operates to discharge to the power feeding system as the SOC of the second storage battery 12 increases, and operates to regenerate from the power feeding system to the transformer secondary side AC system 19 as the SOC decreases.

[0070] In the third embodiment, the same operations as those in the first embodiment can be performed, but the description thereof will be omitted here to avoid duplication.

[0071] (Effects of the third embodiment) According to the third embodiment described above, the second storage battery 12, the power conditioner 32, and the electric vehicle charger 15 are arranged on the AC side. As a result, these devices can be configured using general consumer products, eliminating the need to develop these devices exclusively. This makes it possible to reduce the manufacturing cost of the power supply device 7.

[0072] [Other embodiments] It should be noted that the present invention is not limited to the above-mentioned embodiments. For example, the second and third embodiments can be combined. For example, the first storage battery 9 in the third embodiment may be configured to be connected to the second DC / DC converter 10 via a DC contactor 28.

[0073] In short, this invention is not limited to the above-mentioned embodiment, and various modifications can be made in the implementation stage without departing from the gist of the invention. Moreover, each embodiment may be implemented in combination as appropriate as possible, in which case the combined effect can be obtained. Furthermore, the above-mentioned embodiment includes inventions at various stages, and various inventions can be extracted by appropriate combinations of the disclosed constituent elements. [Explanation of symbols]

[0074] 1-1…AC system 1-2…AC system 2. Substation 3. Electric wires, overhead lines, third rails 4…Rail 5…Building 6…Electric contactor 7...Power supply device 8...Charging and discharging converter 9…First storage battery 10...Second DC / DC converter 11…Inverter 12…Second battery 13...Solar panel 14...First DC / DC converter 15…Electric vehicle charger 16…Electric car 17...Inverter AC output system 18…First transformer 19... Transformer secondary AC system 20...First AC contactor 21...Second AC contactor 22...Third contactor 23...Fourth AC contactor 24…Second transformer 25…Load 26…DC power supply device 27…DC power supply path 28…DC contactor 29...Control section 30…Train 31...5th AC contactor 32...Power conditioner

Claims

1. A power supply device connected to a substation that converts AC to DC and outputs it, and to a feeder circuit that is connected to an electric vehicle that serves as a load, a first power converter connected to the feeding circuit and configured to convert a voltage of the feeding circuit into an arbitrary voltage; a first storage battery connected to the first power converter and the solar panel; a control unit that controls the power generated by the solar panel to be supplied to the first storage battery; A power supply device comprising:

2. 2. The power supply device according to claim 1, wherein the control unit controls the power converter and the first storage battery so that the higher the charging rate of the first storage battery, the higher at least one of a charging threshold voltage and a power supply threshold voltage for the feeding circuit becomes.

3. 2. The power supply device according to claim 1, wherein the control unit controls the power converter and the first storage battery so that the lower the charging rate of the first storage battery, the lower at least one of a charging threshold voltage and a power supply threshold voltage for the feeding circuit becomes.

4. 2. The power supply device according to claim 1, further comprising a second power converter connected to the first storage battery and converting a discharge voltage of the first storage battery into a given DC voltage.

5. an inverter connected to the first storage battery and configured to convert a discharge voltage of the first storage battery into an arbitrary AC voltage; The power supply device according to claim 1 , wherein the solar panel is connected to the first storage battery via the inverter.

6. an inverter connected to the first storage battery and configured to convert a discharge voltage of the first storage battery into an arbitrary AC voltage; a first transformer connected to an AC output side of the inverter; a DC power supply device connected to the first transformer, converting an AC voltage output from the first transformer into a DC voltage, and supplying a control power source for monitoring and controlling the first power converter and the first storage battery; The power supply device according to claim 1 , further comprising:

7. The power supply device according to claim 6 , wherein the DC power supply device is supplied with power from power generated by the solar panel.

8. 2. The power supply device according to claim 1, wherein, when the substation cannot supply power to the power feeding circuit, the control unit charges the first storage battery with power generated by the solar panel and supplies the power charged in the storage battery to the power feeding circuit via the first power converter.

9. an inverter connected to the first storage battery, converting a discharge voltage of the first storage battery into an arbitrary AC voltage, and controlled by the control unit; a first transformer connected to an AC output side of the inverter and to a commercial AC power line to which AC power is supplied; 2. The power supply device according to claim 1, wherein the control unit controls the first power converter, the first storage battery, and the inverter so as to supply regenerative power generated by the electric vehicle to the commercial AC power line as the charging rate of the first storage battery increases, and to increase power supply from the commercial AC power line to the first storage battery as the charging rate of the first storage battery decreases.

10. 2. The power supply device according to claim 1, further comprising: a second storage battery connected to the first storage battery and the solar panel and including a second power converter, wherein the second storage battery is controlled by the control unit.

11. 11. The power supply device according to claim 10, wherein the control unit controls the second power converter to increase the power supply to the first storage battery as the storage rate of the second storage battery increases, and controls the second power converter to increase the power supply to the second storage battery as the storage rate of the second storage battery decreases.

12. The power supply device according to claim 1 , wherein the first storage battery is neutral-grounded.

13. The first storage battery is connected to an electric vehicle charger; the control unit further controls the first storage battery so that the power generated by the solar panel is supplied to the electric vehicle charger; the electric vehicle charger charges an electric vehicle connected to the electric vehicle charger using at least one of the power generated by the solar panel and the power discharged from the first storage battery; The power supply device of claim 1 .

14. Further comprising an inverter connected to the first storage battery and converting the discharge voltage of the first storage battery into an arbitrary AC voltage; The power supply device according to claim 13 , wherein the solar panel is connected to the electric vehicle charger via the inverter.

15. A power supply device as described in claim 13, further comprising a second storage battery connected to the first storage battery, the solar panel, and the electric vehicle charger and having a second power converter, wherein the second storage battery is controlled by the control unit.

16. A power supply device as described in claim 1, further comprising a DC / DC converter connected to the solar panel and the first storage battery, for converting the power generated by the solar panel into a voltage used in the first storage battery.

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