Power supply device

Abstract

The present invention provides a power supply device capable of establishing a redundant commercial power supply system for supplying power to a load. [Solution] The power supply device comprises: a second power converter whose primary side is connected to a power supply circuit and which, as the voltage of the power supply circuit rises, transforms the voltage value of the output power of the power supply circuit to a predetermined voltage value to charge the second storage battery; a second storage battery connected to the secondary side of the second power converter and charged by the output power from the second power converter; a third power converter connected to the secondary side of the second storage battery and which supplies the charging power of the second storage battery to the load; and a second contactor whose primary side is connected to the third power converter via a second transformer and whose secondary side is connected to the load and the first contactor. When the first contactor is open and the second contactor is closed, the second storage battery, the electric vehicle connected to the power supply circuit, the substation, or the power storage device supplies power to the load using the third power converter.

Description

Technical Field

[0001] Embodiments of the present invention relate to a power supply device.

Background Art

[0002] Currently, in DC electric railways, the railway system is operated by receiving power from a high-voltage power distribution system of commercial alternating current (50 Hz / 60 Hz) for a power feeding system that supplies power to trains and auxiliary equipment such as stations, substations, and signals. This high-voltage power distribution system usually receives power at a substation that supplies direct current to a DC power feeding circuit, converts it to an arbitrary voltage using a transformer, and distributes it to AC loads. On the other hand, measures such as laying a standby line for power supply from an adjacent substation in case the power receiving system of the substation stops, or conversely, receiving power from another commercial system at the substation to ensure system redundancy are implemented.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, Patent Document 1 describes constructing a microgrid that can be economically established using an electric railway system. Specifically, a method of connecting and operating the power of a power feeding line to the commercial power system through a power meter for power extraction that measures the amount of power in the commercial power system is described. Also, for example, Patent Document 2 describes a method of supplying the energy of a power feeding circuit to a DC control power supply through a power storage device.

[0005] However, Patent Document 1 does not clarify specific methods for dealing with a power outage in the commercial power grid or for establishing an independent AC power grid without being connected to the commercial power grid. Patent Document 2 does not clarify specific methods for establishing an independent commercial frequency grid.

[0006] Furthermore, the power supply within substations and the commercial frequency power supplied to stations or signaling equipment require redundancy and are often supplied via multiple power receiving lines. Laying and maintaining these power receiving lines incurs costs.

[0007] Embodiments of the present invention have been made in view of the above circumstances, and aim to provide a power supply device capable of establishing a redundant commercial power supply system for supplying power to a load. [Means for solving the problem]

[0008] A power supply device according to one embodiment includes a power storage device having a first storage battery that is charged and discharged via a first power converter, and a power supply device having a power supply circuit whose primary side is connected to a power supply circuit having a power supply circuit having a power supply circuit having a power supply circuit having a power supply circuit having a power supply circuit having a power supply circuit that rectifies and supplies AC power supplied from a first AC system, and a first contactor connected to a first transformer that transforms AC power supplied from a second AC system, and a load connected to a power supply device whose primary side is connected to the power supply circuit, and a second power converter which, as the voltage of the power supply circuit rises, transforms the voltage value of the output power of the power supply circuit to a predetermined voltage value to charge the second storage battery, and the secondary side of the second power converter The power storage device comprises a second battery connected and charged by the output power from the second power converter, a third power converter connected to the secondary side of the second battery and supplying the charging power of the second battery to the load, and a second contactor whose primary side is connected to the third power converter via a second transformer and whose secondary side is connected to the load and the first contactor, wherein when the first contactor is open and the second contactor is closed, the second battery, the electric vehicle connected to the power supply circuit, the substation, or the power storage device supplies power to the load using the third power converter. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 shows an example configuration of a power supply system including a power supply device according to the first embodiment. [Figure 2] Figure 2 shows an example configuration of a power supply system including a power supply device according to the second embodiment. [Figure 3] Figure 3 shows an example configuration of a power supply system including a power supply device according to the third embodiment. [Modes for carrying out the invention]

[0010] The following describes in detail several power supply devices according to various embodiments, with reference to the drawings. Note that the scale of each part in the drawings used in the following descriptions of embodiments has been appropriately changed. Also, in the drawings used in the following descriptions of embodiments, some components may be omitted for illustrative purposes.

[0011] [First Embodiment] Figure 1 is a diagram showing an example configuration of a power supply system including a power supply unit 17 according to the first embodiment. The power supply system shown in Figure 1 comprises an electric vehicle 3, a power supply circuit, a first AC system 9, a second transformer 10, a first contactor 11, a load 13, and a power supply unit 17.

[0012] Electric train 3 runs by collecting power from the overhead line 1 or the third rail, for example, using a current collector. In Figure 1, there is one electric train 3 on the rail 2, but there may be multiple electric trains 3 on the same rail 2.

[0013] The power supply circuit comprises an overhead line 1, rails 2, a substation, and a power storage device. The overhead line 1 may be a third rail.

[0014] The substation comprises a rectifier 14, a rectifier transformer 15, and a second AC power system 16. The rectifier 14, the rectifier transformer 15, and the second AC power system 16 are electrically connected to each other. The rectifier transformer 15 receives three-phase AC power from the second AC power system 16, converts the three-phase AC power into DC power, and transmits the DC power to the power supply circuit via the rectifier 14.

[0015] The power storage device comprises a first power converter 4 and a first battery 51. The first power converter 4 is electrically connected on one end to the overhead line 1 and rail 2, and on the other end to the first battery.

[0016] For example, the first power converter 4 is a DC / DC converter that has the function of converting the overhead line voltage to the battery voltage. The first power converter 4 converts the regenerative power from the regenerative braking of the electric vehicle 3 and charges the first battery 51. The first power converter 4 also converts power from the substation and charges the first battery 51. The first power converter 4 may also convert power from the power supply unit 17 and charge the first battery 51. The first power converter 4 discharges the charged power stored in the first battery 51 according to the voltage of the overhead line 1.

[0017] The power supply unit 17 is a device that connects one side (primary side) to the power supply circuit and the other side (secondary side) to the first contactor 11 and the load 13, and comprises a second power converter 6, a second storage battery 52, a third power converter 7, a first transformer 8, and a second contactor 12.

[0018] The second power converter 6 connects one side (primary side) to the power supply circuit and the other side (secondary side) to the second battery 52. ​​The second power converter 6 is a DC / DC converter that has the function of converting the overhead line voltage to the battery voltage and charges and discharges the second battery 52.

[0019] For example, as the voltage of the power feeding circuit rises, the second power converter 6 transforms the voltage value of the output power of the power feeding circuit to a predetermined voltage value to charge the second storage battery 52. Also, as the voltage of the power feeding circuit drops due to a decrease in the state of charge (SOC) of the first storage battery 51, the second power converter 6 transforms the voltage value of the discharge power of the second storage battery 52 to a predetermined voltage value and outputs it to the power feeding circuit.

[0020] When the voltage of the overhead line 1 rises because the electric vehicle 3 applies brakes, the second power converter 6 compares the voltage of the overhead line 1 with the charging start voltage threshold value. When the second power converter 6 determines that the voltage of the overhead line 1 has exceeded the charging start voltage threshold value, it starts charging the second storage battery 52.

[0021] Also, the second power converter 6 monitors the state of charge (SOC) of the second storage battery 52. The second power converter 6 sets the threshold value of the charging start voltage from the power feeding circuit according to the state of charge (SOC) of the second storage battery 52. That is, when the second power converter 6 detects a decrease in the state of charge (SOC) of the second storage battery, it sets the charging start voltage threshold value from the power feeding circuit low. Also, when the second power converter 6 detects an increase in the state of charge (SOC) of the second storage battery, it sets the charging start voltage threshold value from the power feeding circuit high.

[0022] The second storage battery 52 is configured, for example, as a lithium-ion secondary battery including an electrode group in which a positive electrode and a negative electrode are laminated via a separator. Also, the second storage battery 52 may be configured as a large-capacity capacitor.

[0023] The second storage battery 52 is charged by the output power of the second power converter 6. The second storage battery 52 includes, for example, a circuit that calculates the state of charge (SOC) using the charge and discharge current value of the second storage battery 52 measured by a current sensor and the voltage value of the second storage battery 52 measured by a voltage sensor, and periodically or in response to a request, transmits the calculated state of charge (SOC) to the second power converter 6.

[0024] The third power converter 7 is connected to the second battery 52 on one side (primary side) and to the first transformer 8 on the other side (secondary side). The third power converter 7 is, for example, a three-phase inverter that converts the battery voltage to an arbitrary AC voltage, and it converts the voltage of the charging power of the second battery to an arbitrary AC voltage and supplies it to the load 13. It is desirable that the first power converter 4, the second power converter 6, and the third power converter 7 are equipped with specifications that allow current to flow continuously.

[0025] The first transformer 8 transforms the voltage of the AC power converted by the third power converter 7. The second contactor 12 opens and closes based on commands from a higher-level device. When the second contactor 12 is closed, the charging power of the second battery can be supplied to the load 13.

[0026] The first AC power system 9 uses the second transformer 10 to step down the voltage of the AC power and supplies it to the load 13. The first contactor 11 opens and closes based on commands from a higher-level device. When the first contactor 11 is closed, the AC power of the first AC power system 9 can be supplied to the load 13. The first AC power system 9 and the second AC power system 16 may receive power from the same higher-level system, or they may receive power from different higher-level systems.

[0027] Load 13 is an AC load that receives power from the first AC system 9 and the power supply device 17, and may be, for example, a DC control power supply device that converts AC to DC within a substation, air conditioning equipment within a substation, a signaling system necessary for the operation of a railway system, a power supply for a level crossing, a power supply for station equipment, etc.

[0028] Next, the specific operation of the power supply system, including the power supply unit 17, will be described. For example, when the first contactor 11 is closed and the second contactor is closed, the power supply unit 17 supplies power from the power supply circuit to the load 13. Also, when the first contactor 11 is closed and the second contactor is closed, the load 13 also receives power from the first AC system. It is assumed that the distribution of power supply is managed by a higher-level device according to the type of load 13.

[0029] If the power supply to the load 13 of the first AC system 9 is interrupted due to a disconnection or power outage, the higher-level device detects the disconnection and power outage and sends a signal to the power supply unit 17 and the first contactor 11 to notify them and perform control. The third power converter 7 of the power supply unit 17 stops switching operation based on the signal from the higher-level device.

[0030] Next, the higher-level device controls the first contactor 11 to open it. The second contactor 12 remains closed. When the first contactor 11 is open and the second contactor 12 is closed, the third power converter 7 starts switching. As a result, the power supply unit 17 supplies power from the power supply circuit to the load 13, enabling the power supply unit 17 to operate the load 13 independently.

[0031] Furthermore, the third power converter 7 may be configured to start with a soft start, gradually increasing the output voltage when switching operation begins. This prevents overshoot, where the output voltage exceeds the set voltage, and also prevents damage to the load 13.

[0032] For example, when power charged in the second battery 52 is supplied to the load 13 via the third power converter 7, the second power converter 6 monitors the state of charge (SOC) of the second battery 52. ​​When the SOC of the second battery 52 decreases, the second power converter 6 detects the decrease in charge.

[0033] The second power converter 6 changes the setting of the charging start voltage threshold from the power supply circuit (overhead line 1). The second power converter 6 lowers the setting of the charging start voltage threshold and charges the second battery 52 with power from the power supply circuit. The third power converter 7 may supply power from the second battery 52 to the load 13 even when the second power converter 6 is charging the second battery 52.

[0034] As a result of the above, it becomes possible to supply power from the power supply circuit to the load 13 via the second power converter 6 and the second storage battery 52, and by making the third power converter 7 an AC system, the power supply unit 17 can operate independently for the load 13.

[0035] Furthermore, if power can be supplied to the load 13 from the second AC system 16, the power supply unit 17 may receive the power output by the rectifier 14 via the power supply circuit and continuously supply power to the load 13.

[0036] Furthermore, since the first AC system 9 and the second AC system 16 receive power from the same upstream system, if the same upstream system becomes unable to supply power due to a power outage, disconnection, etc., it becomes possible to supply power to the load 13 by transmitting the power stored in the first battery 51 of the power storage device to the power supply device 17 via the first power converter 4 and the power supply circuit. In this case, the first power converter 4 operates as a constant voltage source to maintain the voltage of the overhead line 1.

[0037] Furthermore, the first power converter 4 has a function to monitor the state of charge (SOC) of the first battery 51. For example, when the first power converter 4 detects a decrease in the SOC of the first battery 51, it controls the output voltage to decrease. Also, if there are multiple power storage devices comprising the first power converter 4 and the first battery 51 in the power supply circuit, the power stored in each of the multiple first batteries 51 may be used equally and transmitted to the power supply device 17 via the power supply circuit to supply power to the load 13.

[0038] Furthermore, when the electric vehicle 3 applies the brakes and the voltage of the overhead line 1 rises, the second power converter compares the voltage of the overhead line 1 with the charging start voltage threshold. When it detects that the voltage of the overhead line 1 has exceeded the charging start voltage threshold, it starts charging the second battery 52, making it possible to supply the regenerative power of the electric vehicle 3 to the load 13.

[0039] According to the power supply device 17 of this embodiment, compared to ensuring redundancy in power supply to the load by receiving power from multiple AC systems at the substation, it is possible to reduce the number of AC power receiving lines, and redundancy can be ensured by configuring the system to supply power to the load using two power systems, the AC system and the power supply circuit. [Second Embodiment] The second embodiment is a configuration of the power supply unit 17 according to the first embodiment, excluding the second power converter 6 and the second storage battery 52. ​​Other functional configurations are the same as in the first embodiment, so their description is omitted. Figure 2 shows an example configuration of a power supply system including the power supply unit according to the second embodiment.

[0040] The third power converter 7 according to this embodiment connects one side (primary side) to the power supply circuit and the other side (secondary side) to the first transformer 8. The third power converter 7 is, for example, a three-phase inverter that converts the power supply circuit voltage to an arbitrary AC voltage.

[0041] If the power supply to the load 13 of the first AC system 9 is interrupted due to a disconnection or power outage, the higher-level device detects the disconnection and power outage and sends a signal to the power supply unit 17 and the first contactor 11 to notify them and perform control. The third power converter 7 of the power supply unit 17 stops switching operation based on the signal from the higher-level device.

[0042] Next, the higher-level device controls the first contactor 11 to open it. The second contactor 12 remains closed. When the first contactor 11 is open and the second contactor 12 is closed, the third power converter 7 starts switching. As a result, the power supply unit 17 supplies power from the power supply circuit to the load 13, enabling the power supply unit 17 to operate the load 13 independently.

[0043] Furthermore, if power can be supplied to the load 13 from the second AC system 16, the power supply unit 17 may receive the power output by the rectifier 14 via the power supply circuit and continuously supply power to the load 13.

[0044] Furthermore, since the first AC system 9 and the second AC system 16 receive power from the same upstream system, if the same upstream system becomes unable to supply power due to a power outage, disconnection, etc., it becomes possible to supply power to the load 13 by transmitting the power stored in the first battery 51 of the power storage device to the power supply device 17 via the first power converter 4 and the power supply circuit. In this case, the first power converter 4 operates as a constant voltage source to maintain the voltage of the overhead line 1.

[0045] Furthermore, the first power converter 4 has a function to monitor the state of charge (SOC) of the first battery 51. For example, when the first power converter 4 detects a decrease in the SOC of the first battery 51, it controls the output voltage to decrease. Also, if there are multiple power storage devices comprising the first power converter 4 and the first battery 51 in the power supply circuit, the power stored in each of the multiple first batteries 51 may be used equally and transmitted to the power supply device 17 via the power supply circuit to supply power to the load 13.

[0046] Furthermore, if the voltage of the overhead line 1 rises when the electric vehicle 3 applies the brakes, it becomes possible to supply power to the load 13 using the regenerative power generated by the electric vehicle 3.

[0047] According to the power supply device 17 of this embodiment, compared to ensuring redundancy in power supply to the load by receiving power from multiple AC systems at the substation, as in the first embodiment, it is possible to reduce the number of AC power receiving lines, and redundancy can be ensured by configuring the system to supply power to the load using two power systems: the AC system and the power supply circuit. [Third Embodiment] The third embodiment is a configuration of the power supply unit 17 according to the first embodiment with the addition of a fourth power converter 18, and the omission of the second power converter 6 and the second storage battery 52. ​​The other functional configurations are the same as in the first embodiment, so their description is omitted. Figure 3 is a diagram showing an example configuration of a power supply system including the power supply unit according to the third embodiment.

[0048] The power supply device 17 according to this embodiment is a device that connects one side (primary side) to a power supply circuit and the other side (secondary side) to a load 13, and comprises a plurality of fourth power converters 18, a plurality of first transformers 8 corresponding to the fourth power converters 18, and a plurality of second contactors 12 corresponding to the fourth power converters 18.

[0049] In Figure 3, there are two of each of the fourth power converter 18, the first transformer 8, and the second contactor 12, but this is not limited to two; there may be three or more of each. Also, the first AC system 9, the second transformer 10, and the first contactor 11, which are not shown, may be connected to the load 13 and the secondary side of the power supply unit 17.

[0050] The fourth power converter 18 connects one side (primary side) to the power supply circuit and the other side (secondary side) to the first transformer 8. The fourth power converter 18 is, for example, a three-phase inverter that converts the power supply circuit voltage to any AC voltage.

[0051] In the configuration shown in Figure 3, one of the second contactors 12 is in the closed state, while the other remains in the open state. The fourth power converter 18 connected to the closed second contactor 12 is put into operation, and power from the power supply circuit is supplied to the load 13 using the operational fourth power converter 18. The fourth power converter 18 connected to the open second contactor 12 remains in standby mode, enabling the power supply unit 17 to operate independently for the load 13.

[0052] Furthermore, if power can be supplied to the load 13 from the second AC power system 16, the power supply unit 17 may receive the power output by the rectifier 14 via the power supply circuit and continuously supply power to the load 13 using the operating fourth power converter 18.

[0053] Furthermore, if the second AC power system 16 becomes unable to supply power due to a power outage or disconnection, the power stored in the first battery 51 of the power storage device is transmitted to the power supply unit 17 via the first power converter 4 and the power supply circuit, making it possible to supply power to the load 13 using the operational fourth power converter 18. In this case, the first power converter 4 operates as a constant voltage source to maintain the voltage of the overhead line 1.

[0054] Furthermore, the first power converter 4 has a function to monitor the state of charge (SOC) of the first battery 51. For example, when the first power converter 4 detects a decrease in the SOC of the first battery 51, it controls the output voltage to decrease. Also, if there are multiple power storage devices comprising the first power converter 4 and the first battery 51 in the power supply circuit, the power stored in each of the multiple first batteries 51 may be used equally and transmitted to the power supply device 17 via the power supply circuit, thereby supplying power to the load 13 using the operating fourth power converter 18.

[0055] Furthermore, if the voltage of the overhead line 1 rises when the electric vehicle 3 applies the brakes, it becomes possible to supply power to the load 13 using the regenerative power of the electric vehicle 3 via the operating fourth power converter 18.

[0056] According to the power supply device 17 of this embodiment, by duplicating or multiplexing the fourth power converter 18, which is an inverter, and the transformer, it becomes possible to enhance the redundancy of the power supply to the load 13.

[0057] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols]

[0058] 1… Overhead line 2... Rails 3… Electric vehicles 4…First power converter 51…First battery 52...Second battery 6...Second power converter 7…Third power converter 8…First Transformer 9...1st AC system 10… Second Transformer 11...1st contactor 12…Second contactor 13…Load 14... Rectifier 15…Transformer for rectifiers 16…Second AC system 17…Power supply device 18…Fourth Power Converter

Claims

1. A power supply device that connects a power storage device equipped with a first battery that charges and discharges via a first power converter, a power supply circuit having a substation that rectifies and supplies AC power supplied from a first AC system, a first contactor connected to a first transformer that transforms AC power supplied from a second AC system, and a load to the secondary side, A second power converter, the primary side of which is connected to the power supply circuit, and which, as the voltage of the power supply circuit rises, transforms the voltage value of the output power of the power supply circuit to a predetermined voltage value to charge the second storage battery, The second storage battery is connected to the secondary side of the second power converter and is charged by the output power from the second power converter, A third power converter connected to the second battery and supplying the charging power of the second battery to the load, The primary side is connected to the third power converter via the second transformer, and the secondary side is connected to the load and the second contactor which is connected to the first contactor, Equipped with, A power supply device in which, when the first contactor is opened and the second contactor is closed, the second storage battery, the electric vehicle connected to the power supply circuit, the substation, or the power storage device supplies power to the load using the third power converter.

2. A power supply device that connects a power storage device equipped with a first battery that charges and discharges via a first power converter, a power supply circuit having a substation that rectifies and supplies AC power supplied from a first AC system, a first contactor connected to a first transformer that transforms AC power supplied from a second AC system, and a load to the secondary side, A fourth power converter whose primary side is connected to the feeder circuit, which converts the DC regenerative power of the feeder circuit into AC power as the voltage of the feeder circuit rises, The primary side is connected to the fourth power converter via the second transformer, and the secondary side is connected to the load and the second contactor which is connected to the first contactor, Equipped with, A power supply device in which, when the first contactor is open and the second contactor is closed, an electric vehicle connected to the power supply circuit, the substation, or the power storage device supplies power to the load using the fourth power converter.

3. A power supply device that connects the primary side to a power supply circuit having a power storage device equipped with a first storage battery that charges and discharges via a first power converter, and a substation that rectifies and supplies AC power supplied from a first AC grid, and connects the load to the secondary side, Multiple fourth power converters, the primary side of which is connected to the feeder circuit and the secondary side of which is connected to the second transformer, convert the DC regenerative power of the feeder circuit into AC power as the voltage of the feeder circuit rises, A plurality of second contactors, the primary side of which is connected to the corresponding fourth power converter via a second converter, and the secondary side of which is connected to the load, Equipped with, A power supply device in which, when at least one of the second contactors is closed, an electric vehicle connected to the power supply circuit, the substation, or the power storage device supplies power to the load using the corresponding fourth power converter.

4. The power supply device according to claim 1, wherein the second power converter, in response to a decrease in the voltage of the power supply circuit due to a decrease in the charge level of the first storage battery, transforms the voltage value of the discharge power of the second storage battery to a predetermined voltage value and outputs it to the power supply circuit.

5. The power supply device according to claim 1, wherein the second power converter lowers the charging start voltage threshold from the power supply circuit when it detects a decrease in the charge level of the second storage battery.

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