DC power distribution network

Abstract

To allow efficient use of power in a DC power distribution network whose construction cost is suppressed.SOLUTION: A DC power distribution network for a residence comprises a power distribution unit provided with: a supply unit which acquires request voltage and request power of loads such as at least one or more home appliances and electronic appliances connected with the DC power distribution network and supplies power to the loads; a first connection unit which is connected with the supply unit and can bidirectionally supply power with a power system; and a second connection unit which is connected with the supply unit, similarly as the first connection unit, and can bidirectionally supply power with the power system. The power distribution unit controls power to be bidirectionally supplied between each of the first connection unit and the second connection unit according to the acquired request voltage and request power of the loads.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a DC power distribution network. [Background technology]

[0002] Power distribution networks that supply DC power from an outlet to loads such as electrical appliances instead of AC power are known (see, for example, Patent Document 1). Patent Document 1 describes a DC smart outlet that prevents current from flowing to the electrical outlet if it detects a reverse polarity voltage exceeding a threshold. Patent Document 2 also describes a network that transmits data and power using a minimum number of connecting wires. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6895216 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-127806 Summary of the Invention [Problem to be solved by the invention]

[0004] Currently, homes use single-phase 100 volt (V) or 200V AC power distribution to match the connected devices of home appliances, etc., while factories use three-phase 200V or 400V AC power distribution. These AC power distribution systems distribute power from the power grid in a tree-like structure starting from a distribution board. Each connected device receives power via a single line from the distribution board, and no mechanism is implemented for power interchange between outlets distributed throughout a building or room. Therefore, even if a connected device generates excess power, the excess power is not directly supplied to other nearby connected devices. Therefore, there is a demand for efficient use of the surplus power that occurs in such cases. Furthermore, if power from the power grid is cut off due to an accident or other factor, all power supply from the distribution board is stopped. In this case, even if some connected devices in the distribution network have energy storage elements such as storage batteries, there is no way to supply power from the storage batteries to other connected devices. If power interchange between connected devices were to be attempted via a distribution board, a distribution board with a guaranteed power capacity that can accommodate the sum of the power consumption flowing into each connected device and the regenerative power flowing out from each connected device would be required, which could result in the size of the distribution network becoming enormous. Controlling power interchange in AC power distribution requires precise synchronized adjustment of power amplitude, frequency, and phase misalignments. Furthermore, in order to avoid the effects of noise and other factors, control devices using semiconductor switches require additional equipment, such as power factor correction devices and high-performance noise filters, on connected devices. The need for precise synchronized control and additional equipment leads to reduced efficiency, reduced reliability, larger size, and higher costs for connected devices. Therefore, a simplified, low-cost power distribution network was desired.

[0005] The power generated by increasingly widespread photovoltaic cells (PV) and power supplied from storage batteries is DC power. To supply this power to the power grid, existing AC power distribution systems require conversion to commercial-frequency AC voltage, which is inefficient. Furthermore, the complexity of power interchange, such as ensuring AC power quality, requires precise amplitude control and frequency and phase adjustment. Therefore, if a DC power distribution network could be implemented, power interchange would be achieved with simple voltage or current control to combine the power of each power generating device, enabling efficient power utilization. Many of the conventional AC-operated electrical appliances described in Patent Document 1 have internal rectifier circuits, and each internal circuit element often operates on DC, reducing power loss in the rectifier. However, the optimum voltage for many of these electrical appliances differs. For example, the appropriate voltage for home PV is 280 to 450 V, the appropriate voltage for electric vehicle batteries is 280 to 400 V, the appropriate voltage for general home appliances is 140 V (peak value of 100 V AC), the appropriate voltage for LCD TVs and laptop computers is 20 V, and the appropriate voltages for information system electronic circuits and smartphones are 3.3 V and 5 V. Therefore, there is a demand for power to be supplied directly from the power grid to each device at the appropriate voltage.

[0006] The present invention is intended to solve at least part of the above-mentioned problems, and aims to enable efficient use of power in a DC power distribution network while suppressing construction costs. [Means for solving the problem]

[0007] The present invention is intended to solve at least part of the above-mentioned problems, and can be realized in the following aspects.

[0008] (1) According to one aspect of the present invention, there is provided a residential DC power distribution network. The DC power distribution network includes a supply unit that acquires required voltages and powers of at least one or more connected loads, such as home appliances or electronic devices, and supplies power to the loads, a first connection unit that is connected to the supply unit and capable of bidirectionally supplying power to a power grid, and a second connection unit that is connected to the supply unit similarly to the first connection unit and capable of bidirectionally supplying power between the power grid and the supply unit. The power distribution unit supplies power bidirectionally to both the first connection unit and the second connection unit, and controls the power supplied bidirectionally between the first connection unit and the second connection unit in accordance with the acquired required voltages and powers of the loads.

[0009] According to this configuration, the supply unit connected to the first and second connection units, which are capable of supplying power bidirectionally, controls the power exchanged between the first and second connection units according to the voltage and power requirements of the load. Therefore, the power supplied to the load varies depending on the state of the first and second connection units. As a result, the power flowing through the DC power distribution network is autonomously leveled by the power distribution unit. Therefore, this configuration enables efficient use of power. Furthermore, because the power flowing through the DC power distribution network of this configuration is DC, devices for converting AC and DC are not required, reducing power loss and the cost of building the power distribution network.

[0010] (2) In the DC power distribution network of the above aspect, at least one of the supply unit, the first connection unit, and the second connection unit of the power distribution unit may be connected to a device capable of storing power, such as a storage battery, and the power distribution unit may control the power to be supplied in both directions and the power supplied in both directions between the first connection unit and the second connection unit according to the acquired required voltage and required power of the load and the amount of power stored in the storage battery, etc. According to this configuration, since the storage battery is connected to the supply unit, power can be supplied from the storage battery to the load and from the storage battery to the first and second connection units. Furthermore, when excess power is generated in the first and second connection units, the power can be stored in the storage battery via the power distribution unit. In a DC power distribution network of this configuration, a storage battery may be connected to the first and second connection units in addition to the storage battery connected to the supply unit, eliminating the need to centralize the storage battery in one location as in a typical home energy storage system. Therefore, by distributing multiple small-capacity storage batteries across the network, the required capacity of the storage battery for the entire network is ensured. Furthermore, in the event of a battery failure, functionality can be restored by partial replacement and repair, reducing maintenance and management costs.

[0011] (3) In the DC power distribution network of the above aspect, at least one of the supply unit, the first connection unit, and the second connection unit may be connected to another of the power distribution units, and power may be supplied in both directions from either the supply unit, the first connection unit, or the second connection unit of the power distribution unit. A DC power distribution network with this configuration has multiple power distribution units. Therefore, new circuits can be added to the network by simply adding a power distribution unit, and unnecessary power distribution units can be removed. This simplifies and facilitates construction of equipment within the network, resulting in a low-cost, highly expandable network. Furthermore, since failures within the network can be repaired by partial part replacement, a highly maintainable network can be constructed.

[0012] The present invention can be realized in various ways, for example, by a configuration that combines a DC / DC converter, a step-up / step-down circuit, a battery charger / discharger, etc. that can supply power bidirectionally to the power distribution unit, or by a multi-port converter that integrates these functions. There is no limit to the number of loads that can be connected, and the number may be two or more. Furthermore, a power storage device such as a capacitor or a flywheel may be used instead of the battery. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic block diagram of a DC power distribution network according to an embodiment of the present invention; [Figure 2] FIG. 2 is an explanatory diagram of a power distribution unit. [Figure 3] FIG. 10 is a schematic block diagram of the power flow when the load has high power consumption. [Figure 4] FIG. 10 is a schematic block diagram of the flow of power when the power consumption of the load and the power generated by the PV decrease. [Figure 5] FIG. 10 is a schematic block diagram of the flow of power when the power consumption of the load decreases and the power generated by the PV is in surplus. [Figure 6] FIG. 2 is a schematic block diagram of the flow of power when power is not supplied from the power grid. [Figure 7] FIG. 10 is a schematic block diagram of a DC distribution network according to a second embodiment. [Figure 8] FIG. 1 is a schematic block diagram of an AC power distribution network of a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0014] First Embodiment FIG. 1 is a schematic block diagram of a DC power distribution network 100A according to one embodiment of the present invention. In the DC power distribution network 100A, power is supplied from a power grid 30 to a power distribution unit 10A via a first connection unit 18 and a second connection unit 19. The power is then supplied from the power distribution unit 10A to loads ED, such as home appliances and electronic devices, via a supply unit 12. Variable voltage outlets or the like can be used for the first connection unit 18, the second connection unit 19, and the supply unit 12. By including the power distribution units 10A and 10B as nodes, the DC power distribution network 100A of this embodiment eliminates the need to change or add a power distribution system to a building even if the number or locations of load connections are changed or increased. Furthermore, the power supply between multiple connections is leveled, thereby reducing the construction cost of the DC power distribution network 100A and enabling efficient power utilization within the DC power distribution network 100A.

[0015] 1, a power system 30 that is a power supply source and a DC power distribution network 100A include power distribution units 10A and 10B, loads ED such as home appliances and electronic devices connected to the power distribution units 10A and 10B, and a storage battery 20 that can store power connected to the power distribution unit 10A, etc. The DC power distribution network 100A of this embodiment is a network that allows reverse power flow of power from the power distribution units 10A and 10B and the storage battery 20 to the power system 30.

[0016] Power distribution units 10A and 10B are capable of bidirectional power supply in at least two directions and can supply power to load ED. For example, power distribution unit 10A can supply power bidirectionally to power grid 30 via first connection unit 18 and second connection unit 19, such as a variable voltage outlet. Furthermore, power distribution units 10A and 10B can supply power bidirectionally to each other via supply unit 11, such as a variable voltage outlet. Power distribution unit 10A is connected to storage battery 20 via supply unit 13, which is capable of bidirectional power supply, and therefore can supply power bidirectionally to storage battery 20. Power distribution unit 10A is connected to load ED via supply unit 12, such as a variable voltage outlet, and supplies power to the connected load ED.

[0017] FIG. 2 is an explanatory diagram of the power distribution unit 10A. FIG. 2 shows a detailed block diagram of the power distribution unit 10A and the components connected to the power distribution unit 10A. As shown in FIG. 2, the power distribution unit 10A is configured as a multi-port converter including a transformer core 15 and high-frequency switching circuit units SW11 to SW13, SW18, and SW19. A multi-port converter has multiple ports. Therefore, the power distribution unit 10A exchanges power with the power system 30 connected via connections 18 and 19, the power distribution unit 10B connected via supply unit 11, and the storage battery 20 connected via supply unit 13. The power distribution unit 10A also supplies power to the load ED connected via supply unit 12. The voltage and current of the power exchanged between the power distribution unit 10A and the power system 30 are controlled by the high-frequency switching circuit units SW11 to SW13, SW18, and SW19.

[0018] In FIG. 2, the right side of the wall WL is the outside of the wall WL of the house, which is the so-called living space. On the other hand, the left side of the wall WL is the inside of the house, which is a space sealed off by construction or the like. As shown in FIG. 2, in the supply units 11 and 12, sockets into which plugs of loads ED and the like are inserted are arranged exposed so as to face the outside of the wall WL. Therefore, when a plug of a load ED or the like is inserted into a socket from the wall WL, power is supplied to the load ED from the power distribution units 10A and 10B. Note that FIG. 2 shows a state before the load ED is connected to the supply unit 12.

[0019] In this embodiment, power distribution unit 10A acquires the required voltage and required power of load ED connected to supply unit 12 via a variable voltage outlet. Power distribution unit 10A controls the power supplied bidirectionally between power distribution unit 10B, which is also connected to supply unit 11, first connection unit 18, and second connection unit 19 via a variable voltage outlet, and power grid 30, according to the acquired required voltage and required power of load ED. Note that, to acquire the required voltage and required power of load ED, power distribution unit 10A can use a method such as recording setting information for different required voltages and required powers on the surface of the plug of load ED from the base to the tip of the plug, and providing a mechanism for acquiring the setting information in an insertion hole into which the plug of supply unit 12 is inserted. In this way, power distribution unit 10A can acquire the required voltage and required power of load ED according to the insertion depth of the plug into the insertion hole.

[0020] The output voltage V1 from the power distribution unit 10A to the load can be changed in accordance with changes in the power supplied to the load ED connected to the power distribution unit 10A. Note that the output voltage V1 in this specification is the voltage supplied from the high-frequency switching circuit unit SW12 to the load ED connected to the supply unit 12. When the power and current supplied from the power distribution unit 10A to the load ED increase, the power distribution unit 10A reduces the output voltage V1, thereby suppressing the power supplied to the load ED. In this embodiment, when the voltage drop in the output voltage V1 of the power distribution unit 10A reaches a set value, the power supplied to the load ED becomes excessive, and the power supply from the power distribution unit 10A to the load ED stops.

[0021] The supply unit 13 of the power distribution unit 10A, which does not use a variable voltage outlet, functions as a charger / discharger for the storage battery 20. When the power exchanged between the supply unit 13 and the storage battery 20 changes, the power distribution unit 10A can change the battery voltage V2. The battery voltage V2 is the voltage value of the supply unit 13, which connects the high-frequency switching circuit unit SW13 and the storage battery 20. When power is supplied from the power distribution unit 10A to the storage battery 20, the amount of electricity stored in the storage battery 20 increases, and the battery voltage V2 of the power distribution unit 10A rises.

[0022] In this embodiment, a discharge stop voltage and a charge stop voltage are set as thresholds for the amount of stored power in the storage battery 20. The power distribution unit 10A controls the power supplied to the load ED and the power supplied bidirectionally between the power grid 30 and the power distribution unit 10A, depending on the required voltage and power of the load ED and the power stored in the storage battery 20. In a state (discharging state) in which power is supplied from the storage battery 20 to the power distribution unit 10A according to the status of the power grid 30, the battery voltage V2 decreases as the amount of stored power decreases. When the amount of stored power reaches a lower limit and the battery voltage V2 reaches the discharge stop voltage, the power supply from the storage battery 20 to the power distribution unit 10A is stopped, thereby preventing excessive discharge of the storage battery 20.

[0023] Conversely, in a state where power is being supplied from the power distribution unit 10A to the storage battery 20 (charging state), the battery voltage V2 rises as the amount of stored power increases. When the amount of stored power reaches its upper limit and the battery voltage V2 reaches the charging stop voltage, the power supply from the power distribution unit 10A to the storage battery 20 is cut off, and excessive charging of the storage battery 20 is prevented.

[0024] The power distribution unit 10A can change the output end voltage V3 in accordance with changes in the power exchanged with the power grid 30 connected via the first connection unit 18. The output end voltage V3 is the voltage value of the first connection unit 18 via the high-frequency switching circuit unit SW18. When the power supplied from the power grid 30 to the power distribution unit 10A increases, the output end voltage V3 decreases. On the other hand, when the power supplied from the power distribution unit 10A to the power grid 30 increases, the output end voltage V3 increases.

[0025] In this embodiment, the power distribution unit 10A acquires the reference voltage of the power grid 30 in advance. The power distribution unit 10A controls the power consumption of the load ED and the power transferred between the storage battery 20 and the power distribution unit 10B. If the sum of these powers exceeds the output, the power distribution unit 10A receives power from the power grid 30. As the power supplied from the power grid 30 increases, the output terminal voltage V3 is reduced from the reference voltage. If the voltage drop of V3 reaches a set value, the power supplied from the power grid 30 to the power distribution unit 10A becomes excessive, and the power supply to the load is stopped. The DC power distribution network 100A of this embodiment allows reverse power flow from the power distribution unit 10A to the power grid 30. Therefore, if the sum of the power supplied to the load ED and the power transferred between the storage battery 20 exceeds the input, the power distribution unit 10A supplies power to the power grid 30. In this state, the output terminal voltage V3 is increased from the reference voltage as the power supplied to the power grid 30 increases. When the voltage rise of V3 reaches a set value, the power supplied from the power distribution unit 10A to the power grid 30 becomes excessive, and the power supply to the power grid 30 is stopped. In this embodiment, the output end voltages V1, V3 and the battery voltage V2 are set independently according to the connected load ED, etc., and the supplied power is controlled, thereby supplying power according to the characteristics of the load ED, etc., connected to the power distribution unit 10A. As a result, stable autonomous decentralized power control is performed in the DC power distribution network 100A of this embodiment.

[0026] 3 to 6 are explanatory diagrams of the flow of power in a DC power distribution network 100B. Schematic block diagrams of the DC power distribution network 100B, each of which has a different power flow, are shown in FIGS. 3 to 6. In the DC power distribution network 100B shown in FIGS. 3 to 6, the direction of the power flow in each wiring is represented by the direction of the arrow, and the magnitude of the power is represented by the thickness of the arrow and the wiring. For example, in FIG. 3, the magnitude of the power supplied from the power distribution unit 10D to the load ED is the largest among the powers flowing in the other wirings.

[0027] 3 to 6, the DC power distribution network 100B includes three power distribution units 10C to 10E, two storage batteries 20A and 20B, two PVs 40A and 40B, and a load ED connected to the power distribution unit 10D. In this embodiment, the two PVs 40A and 40B are solar cells that generate power using sunlight and supply it to the DC power distribution network 100B.

[0028] The power system 30 is connected to two power distribution units 10D, 10E and supplies power to the connected power distribution units 10D, 10E. The DC power distribution network 100B may be a network capable of reverse power flow, which allows power to be supplied from the power distribution units 10D, 10E to the power system 30. The power distribution unit 10D is connected to a load ED and two power distribution units 10C, 10E. The power distribution unit 10D supplies power to the load ED. Furthermore, power can be supplied to each other between the power distribution unit 10D and the power distribution units 10C, 10E.

[0029] In addition to power distribution unit 10D, power distribution unit 10C is connected to PV 40A and storage battery 20A. Power distribution unit 10C is supplied with power generated by PV 40A, which is connected to it. Power distribution unit 10C also exchanges power with storage battery 20A, which is connected to it. Power distribution unit 10E is connected to power system 30 and power distribution unit 10C, as well as to PV 40B and storage battery 20B. Power distribution unit 10E is supplied with power from PV 40B, which is connected to it. Power distribution unit 10E also exchanges power with storage battery 20B, which is connected to it.

[0030] 3 shows the flow of power when the power consumption of the load ED connected to the power distribution unit 10D is temporarily high. In this case, power is supplied to the load ED from the power system 30, two storage batteries 20A and 20B, and two PVs 40A and 40B via the power distribution unit 10D. The total power of the PV 40A and storage battery 20A is supplied to the power distribution unit 10D via the power distribution unit 10C. The total power of the power system 30, the PV 40B, and storage battery 20B is supplied to the power distribution unit 10D via the power distribution unit 10E. The power distribution unit 10D supplies the power supplied from the power system 30, the power distribution unit 10C, and the power distribution unit 10E to the load ED.

[0031] Fig. 4 shows the flow of power when the power consumption of the load ED decreases and the power generation of the two PVs 40A and 40C decreases from the state shown in Fig. 3. Therefore, in Fig. 4, the power supplied from the PV 40A to the power distribution unit 10C and the power supplied from the PV 40B to the power distribution unit 10E are reduced compared to Fig. 3. In addition, the power supplied from the power distribution unit 10D to the load ED is reduced.

[0032] FIG. 5 shows the flow of power when the power consumption of the load ED decreases from the state shown in FIG. 3 and the power generated by the two PVs 40A and 40B is in excess. In the state shown in FIG. 5, the power distribution unit 10C connected to the PV 40A supplies a portion of the power generated by the PV 40A to the storage battery 20A. As a result, the storage battery 20A enters a charging state rather than a discharging state as shown in FIG. 3, thereby increasing the amount of stored power. Similarly, the power distribution unit 10E connected to the PV 40B supplies a portion of the power generated by the PV 40B and the power supplied from the power grid 30 to the storage battery 20B. As a result, the storage battery 20B enters a charging state and increases the amount of stored power.

[0033] FIG. 6 shows the flow of power when a power outage occurs due to a disaster or the like and power is not supplied from the power grid 30. In this case, the two power distribution units 10D and 10E connected to the power grid 30 do not receive power from the power grid 30. The power distribution unit 10C supplies the sum of the power generated by the PV 40A and the discharged power of the storage battery 20A to the power distribution unit 10D. Similarly, the power distribution unit 10E supplies the sum of the power generated by the PV 40B and the discharged power of the storage battery 20B to the power distribution unit 10D. The power distribution unit 10D supplies the sum of the powers supplied from the two power distribution units 10C and 10E to the load ED.

[0034] As described above, in the DC power distribution network 100A of this embodiment, as shown in FIGS. 1 and 2 , the power distribution unit 10A can supply power bidirectionally between the storage battery 20 and the power grid 30 via the supply unit 13, the first connection unit 18, and the second connection unit 19. The power distribution unit 10A acquires the required voltage and required power of the load ED connected via the supply unit 12, for example. The power distribution unit 10A controls the power supplied bidirectionally between the power distribution unit 10B connected via the supply unit 11, the first connection unit 18, the second connection unit 19, and the supply unit 13 and the power grid 30 and the storage battery 20, in accordance with the power consumption of the load ED. In this embodiment, the power distribution unit 10A, which is connected to the storage battery 20, the power grid 30, and the power distribution unit 10B that can supply power bidirectionally, controls the power exchanged between the storage battery 20, the power grid 30, and the power distribution unit 10B in accordance with the power consumption of the load ED. Therefore, the power supplied to the load ED varies depending on the states of the storage battery 20, the power system 30, and the power distribution unit 10B. As a result, the power flowing through the DC power distribution network 100A is autonomously leveled by the power distribution units 10A and 10B. Therefore, by using the DC power distribution network 100A, efficient use of power becomes possible. Furthermore, because the power flowing through the DC power distribution network 100A is DC, devices for converting AC to DC are not required, which reduces power loss and suppresses the construction costs of the DC power distribution network 100A.

[0035] Furthermore, the power distribution unit 10A of this embodiment is connected to the storage battery 20 via the supply unit 13, enabling bidirectional power supply between the power distribution unit 10A and the storage battery 20. In this embodiment, the storage battery 20 is connected to the power distribution unit 10A, enabling power supply from the storage battery 20 to the load ED and power supply from the storage battery 20 to the power distribution unit 10B and the power grid 30, which allows reverse power flow. Furthermore, when excess power is generated in the power grid 30 and the power distribution unit 10B, power can be stored in the storage battery 20 via the power distribution unit 10A. In the DC power distribution network 100A of this embodiment, a storage battery may be connected to the power distribution unit 10B in addition to the storage battery 20 connected to the power distribution unit 10A. This eliminates the need for the storage batteries to be centrally located, as in the case of household storage batteries. Therefore, by distributing small-scale storage batteries throughout the DC power distribution network 100A, the storage batteries with the required capacity can be secured for the entire DC power distribution network 100A through partial replacement and repair. In addition, in the event of a battery failure, functionality can be restored through partial replacement or repair, reducing maintenance and management costs.

[0036] Furthermore, the power distribution unit 10A and the power distribution unit 10B of this embodiment can supply power bidirectionally to each other via the supply unit 11. In this embodiment, when the power consumption of the load ED connected to the power distribution unit 10A increases, the power supply to the load ED can be covered by the power supplied from the storage battery 20 in addition to the power supplied from the power grid 30. On the other hand, when there is surplus power supplied from the power grid 30, the surplus power is charged to the storage battery 20. In this embodiment, the storage battery 20 is charged and discharged depending on the power consumption of the load ED and the power supplied from the power grid 30. This suppresses sudden changes in the power supplied from the power grid 30 and reduces the maximum value of the power supplied from the power grid 30. This suppresses the upper limit of the contracted power of each household, factory, etc., and suppresses the power margin supplied from the power grid 30 to the DC power distribution network 100A. Furthermore, when the power supply from the power grid 30 is stopped due to a power outage or the like, the storage battery 20 included in the DC power distribution network 100A continues to supply power to the DC power distribution network 100A.

[0037] Furthermore, the power distribution units 10A and 10B of this embodiment control the power supplied to the load ED and the power supplied bidirectionally between the power grid 30 and the power distribution unit 10A, depending on the power consumption of the load ED and the amount of power stored in the storage battery 20. The DC power distribution network 100A of this embodiment includes two power distribution units 10A and 10B. Therefore, new circuits can be added to the network by adding a power distribution unit, and unnecessary power distribution units 10A and 10B can be removed. This simplifies and facilitates installation work within the DC power distribution network 100A, resulting in a low-cost, highly expandable power distribution network. Furthermore, because parts in the DC power distribution network 100A can be partially repaired by replacing them in the event of a failure, a highly maintainable power distribution network can be constructed, allowing for easy replacement and repair.

[0038] Second Embodiment Fig. 7 is a schematic block diagram of a DC power distribution network 100C according to the second embodiment. The DC power distribution network 100C according to the second embodiment includes three power distribution units 10C to 10E and a load ED connected to a power distribution unit 10D. In Fig. 7, as in Figs. 3 to 6, the direction of power flow is indicated by an arrow, and the magnitude of the flowing power is indicated by the thickness of the arrow and the thickness of the wiring.

[0039] As shown in FIG. 7, each of the power distribution units 10C and 10E is connected to the power grid 30 to receive power, and supplies the power to the power distribution unit 10D. The power distribution unit 10D supplies the power supplied from the power grid 30 and the two power distribution units 10C and 10E to the connected load ED. The power distribution unit 10D of the second embodiment controls the power supplied from the power grid 30 and the two power distribution units 10C and 10E to be equalized. Unlike the first embodiment, the DC distribution network 100C of the second embodiment does not include PCs 40A and 40B that generate power and storage batteries 20, 20A, and 20B that can store power. Since the DC distribution network 100C includes multiple power distribution units 10C to 10E, the power supplied from the power grid 30 is equalized among the power distribution units 10C to 10E.

[0040] Fig. 8 is a schematic block diagram of an AC power distribution network 100x of a comparative example. Fig. 8 shows a schematic block diagram of the AC power distribution network 100x in which power is supplied to residential outlets SC1 to SC3 from a power system 30x that supplies AC power. The AC power distribution network 100x shown in Fig. 8 includes the power system 30x, a distribution board 50 that supplies AC power to the outlets SC1 to SC3, the outlets SC1 to SC3 that supply AC power to loads EDx such as connected electronic devices, and the load EDx connected to the outlet SC2.

[0041] In the AC power distribution network 100x of the comparative example, AC power is supplied from the power system 30 to a load EDx connected to an outlet SC2 via a single path, a so-called tree-type power distribution system. Since the load EDx operates on DC power, the load EDx is supplied with DC power converted from AC power by an AC adapter connected to the outlet.

[0042] As described above, the DC power distribution network 100C of the second embodiment includes the power distribution units 10C to 10E as three nodes, as shown in Fig. 7. Therefore, in the second embodiment, the power distribution of the power distribution network is leveled compared to the tree-type AC power distribution network 100x of the comparative example shown in Fig. 8. This allows the capacity of each wiring to be reduced, and the construction cost of the DC power distribution network 100C is suppressed. Furthermore, in the DC power distribution network 100C of the second embodiment, each of the power distribution units 10C to 10E adjusts power in an autonomous and decentralized manner, eliminating the need for a monitoring device such as the distribution board 50 for centralized management as in the comparative example.

[0043] <Modifications of the embodiment> The present invention is not limited to the above-described embodiment, and can be implemented in various forms without departing from the spirit of the present invention, including, for example, the following modifications: In the above-described embodiment, part of the configuration realized by hardware may be replaced by software, and conversely, part of the configuration realized by software may be replaced by hardware.

[0044] In the first and second embodiments, an example of the power distribution unit 10A or the like is described, which is connected to the storage battery 20 or the like as the first connection unit and the second connection unit, and is capable of supplying power to the connected load ED. However, the power distribution unit included in the DC power distribution network can be modified as long as it is capable of supplying power bidirectionally between the two connected first connection unit and the second connection unit and the part where the storage battery is connected as the load. For example, the power distribution unit may not be connected to the power grid 30, but may be connected to the storage battery 20 and the PV 40A, and supply power to the connected load ED. In this case, the power distribution unit may control the charging and discharging of the storage battery 20 or increase or decrease the power supplied to the load ED, depending on the power generated by the PV 40A.

[0045] In the first embodiment, as shown in Fig. 1, the power distribution units 10A and 10B, the storage battery 20, the load ED, and the power system 30 are connected by the supply units 11-13, the first connection unit 18, and the second connection unit 19 so that the connection can be switched, but they may be fixed in a state where the connection cannot be switched. For example, the supply unit 11 shown in Fig. 1 may be omitted, and the two power distribution units 10A and 10B may be fixed and function as a single power distribution unit.

[0046] The power system 30 of the DC power distribution networks 100A to 100C of the first and second embodiments described above may not perform reverse power flow. In this case, the power distribution units 10A to 10E may connect two storage batteries 20 or the like capable of bidirectional power supply to the supply units 11 to 13, and may include one or more supply units capable of supplying power to the load ED or the like. The power system 30 may also be an AC power system 30x or the like. Such a power distribution unit may include, for example, an AC / DC converter that converts AC power to DC power, and may control the exchange of power with the storage batteries 20 or the like depending on the DC power converted from the AC power from the power system 30x and the power consumption of the load ED.

[0047] In the above first embodiment, an example of a method for obtaining the required voltage and required power of the load ED connected to the supply unit 12 is described, but well-known techniques other than those described above can be applied to the method for obtaining the required voltage and required power of the load ED connected to the supply unit 12.

[0048] This aspect has been described above based on embodiments and modifications. However, the above-described embodiments are intended to facilitate understanding of this aspect and are not intended to limit this aspect. This aspect may be modified or improved without departing from the spirit and scope of the claims, and equivalents thereof are included in this aspect. Furthermore, if a technical feature is not described as essential in this specification, it may be deleted as appropriate. [Explanation of symbols]

[0049] 10A~10E...Power distribution unit (multi-port converter) 11~13…Supply section 18...First connection part 19...Second connection part 15...Transformer core of multi-port converter 20,20A,20B…Storage battery 30,30x…power system 50...Distribution board 100A~100C...DC power distribution network 100x…AC distribution network ED, EDx…Load SC1 to SC3: Outlets SW11 to SW13, SW18, SW19...High frequency switching circuit section V1: Output terminal voltage of supply unit 12 V2: Battery voltage of the supply unit 13 V3: Output terminal voltage of the first connection part 18 WL…Wall

Claims

1. 1. A residential DC distribution network, comprising: a power distribution unit including a supply unit that acquires a required voltage and required power of at least one or more connected loads such as home appliances and electronic devices and supplies power to the loads; a first connection unit that is connected to the supply unit and is capable of supplying power bidirectionally to and from the power grid; and a second connection unit that is connected to the supply unit in the same way as the first connection unit and is capable of supplying power bidirectionally to and from the power grid; The power distribution unit power is supplied bidirectionally to the first connection portion and the second connection portion, A DC power distribution network that controls the power supplied bidirectionally between the first connection section and the second connection section in accordance with the acquired required voltage and required power of the load.

2. 2. A DC power distribution network according to claim 1, a device capable of storing power, such as a storage battery, is connected to at least one of the supply unit, the first connection unit, and the second connection unit of the power distribution unit, The power distribution unit controls the power to be supplied in both directions and the power supplied in both directions between the first connection unit and the second connection unit according to the acquired required voltage and required power of the load and the amount of power stored in the storage battery, etc.

3. 2. A DC power distribution network according to claim 1, At least one of the supply unit, the first connection unit, and the second connection unit is connected to another of the power distribution units, A DC power distribution network in which power is supplied bidirectionally from either the supply unit, the first connection unit, or the second connection unit of the power distribution unit.

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