Power supply system, charge and discharge device, power generation device, and signal generation device

Abstract

To provide a power supply system for supplying power from a power generator as needed under a situation where a charging / discharging device and the power generator are connected to each other.SOLUTION: According to a power supply system, a connection switching part 12 constituted in such a manner that a connection path between a charging / discharging device 20 and a power generator 30 is switched to an interconnection path in a normal state case where power is normally supplied from a power system 1, and the connection path between the charging / discharging device 20 and the power generator 30 is switched to an autonomous connection path in an abnormal state case where no power is normally supplied from the power system 1 comprises a signal generator 24 that outputs an autonomous signal to a voltage line constituting the autonomous connection path in the abnormal state case, and that outputs no autonomous signal in the normal state case; and the power generator 30 comprising the signal detection part 35 connected to the voltage line constituting at least the autonomous connection path in the abnormal state case is constituted in such a manner that a signal detection part 35 determines whether or not the autonomous signal is detected.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a charging / discharging device, a power generation device, a power supply system including a connection switching unit that switches a power supply path between the charging / discharging device and the power generation device, a charging / discharging device, a power generation device, and a signal generation device.

Background Art

[0002] Patent Document 1 (Japanese Patent Application Laid-Open No. 2015-35893) describes a power supply system including a storage battery (23), a fuel cell (24), and a connection switching unit (switch 34, switches 55, 56) that switches a power supply path between the storage battery (23) and the fuel cell (24). In this power supply system, in a normal state where power supply from the power grid is being performed normally, by the operation of the connection switching unit, the storage battery (23) and the fuel cell (24) are connected to each other and are connected to the power grid. On the other hand, in an abnormal state where power supply from the power grid is not being performed normally, by the operation of the connection switching unit, the storage battery (23) and the fuel cell (24) are connected to each other and are electrically disconnected from the power grid.

[0003] Also, in the power supply system described in Patent Document 1, a current sensor (37) is provided upstream of a branch breaker (32) to which the fuel cell (24) and a load (60) are connected. And, in a normal state where power supply from the power grid is being performed normally, the fuel cell (24) determines, based on the measurement result of the current sensor (37), whether all the power output from the fuel cell (24) is consumed by the load (60), that is, whether reverse power flow to the power grid is occurring, and controls the output power so that reverse power flow to the power grid does not occur.

[0004] Note that Patent Document 1 also describes disabling the output of the current sensor (37) and allowing power to be supplied from the fuel cell (24) to the storage battery (23).

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2015-35893 [Summary of the Invention] [Problems to be Solved by the Invention]

[0006] In the power supply system described in Patent Document 1, an operation is described in which the output of the current sensor (37) is disabled and power is supplied from the fuel cell (24) to the storage battery (23). However, when the connection switching unit (switch 34, switches 55 and 56) for switching the power supply path between the storage battery (23) and the fuel cell (24) does not operate normally, the storage battery (23) and the fuel cell (24) may not be connected to each other. In that case, the generated power of the fuel cell (24) may flow to the power grid side.

[0007] As configurations of a power supply system including a charge / discharge device, a power generation device, and a connection switching unit for switching the power supply path between the charge / discharge device and the power generation device, there are those shown in FIGS. 1 to 4.

[0008] For example, in the case of the power supply system shown in FIGS. 1 and 2, in a normal state where power supply from the power grid 1 is performed normally, as shown in FIG. 1, the first switching unit 13 switches to a state in which the contact point a and the contact point b are connected, and the switch 14a of the second switching unit 14 switches to a state in which the contact point a and the contact point b are connected, and the switch 14b of the second switching unit 14 switches to a state in which the contact point a and the contact point c are connected. As a result, the power supply path between the charge / discharge device 20 and the power generation device 30 switches to a state in which the charge / discharge device 20 and the power generation device 30 are connected to each other and are connected to the power grid 1. In this case, the general power load device 4 and the important power load device 5 are connected to the power line 2, and power is supplied to each of them. Then, the power generation device 30 controls the generated power so that the generated power does not flow reversely to the power grid 1 with reference to the measurement result of the current measurement unit 11.

[0009] Also, in the case of the power supply system shown in FIGS. 1 and 2, in an abnormal state where the power supply from the power grid 1 is not being carried out normally, as shown in FIG. 2, the first switching unit 13 switches to a state where the contact point a and the contact point c are connected, and the switch 14a of the second switching unit 14 switches to a state where the contact point a and the contact point c are connected, and the switch 14b of the second switching unit 14 switches to a state where the contact point a and the contact point b are connected. As a result, the power supply path between the charge and discharge device 20 and the power generation device 30 switches to a self - contained connection path in a state where the charge and discharge device 20 and the power generation device 30 are connected to each other and electrically disconnected from the power grid 1. In this case, power is supplied to the critical power load device 5, but no power is supplied to the general power load device 4.

[0010] Thus, in the power supply system shown in FIGS. 1 and 2, even if it is an abnormal state where the power supply from the power grid 1 is not being carried out normally, since a voltage supplied from the charge and discharge device 20 is applied to the power generation device 30, from the perspective of the power generation device 30, there is no difference from the case of being connected to the power grid 1. However, as shown in FIG. 2, in the case of an abnormal state where the power supply from the power grid 1 is not being carried out normally, since no current flows through the part where the current measurement unit 11 is provided, there is a problem that the power generation device 30 cannot refer to the measurement result of the current measurement unit 11. And there may be a case where the power generation device 30 is prohibited from supplying generated power in a situation where it cannot refer to the measurement result of the current measurement unit 11.

[0011] Still, even in a situation where the measurement result of the current measurement unit 11 cannot be referred to, as shown in FIG. 2, if it can be confirmed that in an abnormal state where the power supply from the power grid 1 is not being carried out normally and the charge and discharge device 20 and the power generation device 30 are connected to each other, that is, if it can be confirmed that the generated power of the power generation device 30 is not supplied to the power grid 1, it can be said that the generated power of the power generation device 30 may be supplied.

[0012] Similarly, in the case of the power supply system shown in FIGS. 3 and 4, in the normal state where the power supply from the power grid 1 is being carried out normally, as shown in FIG. 3, the third switching unit 15 switches to a state where the contact point a and the contact point b are connected, and the fourth switching unit 16 switches to a state where the contact point a and the contact point b are connected. As a result, the power supply path between the charge / discharge device 20 and the power generation device 30 switches to a state where the charge / discharge device 20 and the power generation device 30 are connected to each other and are connected to the power grid 1. Then, the power generation device 30 controls the generated power so that the generated power does not flow reversely into the power grid 1 while referring to the measurement result of the current measurement unit 11.

[0013] Also, in the case of the power supply system shown in FIGS. 3 and 4, in the abnormal state where the power supply from the power grid 1 is not being carried out normally, as shown in FIG. 4, the third switching unit 15 switches to a state where the contact point a and the contact point c are connected, and the fourth switching unit 16 switches to a state where the contact point a and the contact point c are connected. As a result, the power supply path between the charge / discharge device 20 and the power generation device 30 switches to an independent connection path in a state where the charge / discharge device 20 and the power generation device 30 are connected to each other and are electrically disconnected from the power grid 1.

[0014] Thus, in the power supply system shown in FIGS. 3 and 4, even if it is in an abnormal state where the power supply from the power grid 1 is not being carried out normally, since the voltage supplied from the charge / discharge device 20 is applied to the power generation device 30, from the perspective of the power generation device 30, there is no difference from the case where it is connected to the power grid 1. However, as shown in FIG. 4, in the case of an abnormal state where the power supply from the power grid 1 is not being carried out normally, the power generation device 30 controls the generated power so that the generated power does not flow reversely (in this case, so that the generated power is not supplied to the charge / discharge device 20) while referring to the measurement result of the current measurement unit 11. In this case, since no power is supplied to the charge / discharge device 20, the remaining charge amount of the charge / discharge device 20 may become zero.

[0015] Further, as shown in FIG. 4, if it can be confirmed that the power supply from the power system 1 is not being performed normally and the charging / discharging device 20 and the power generation device 30 are connected to each other, that is, if it can be confirmed that the generated power of the power generation device 30 is not supplied to the power system 1, it can be said that the generated power of the power generation device 30 may be supplied to the charging / discharging device 20 regardless of the measurement result of the current measurement unit 11. The operation of invalidating the output of the current sensor (37) and supplying power from the fuel cell (24) to the storage battery (23) described in Patent Document 1 is considered to be the same as such an idea.

[0016] As described above, regardless of the configuration of the power supply system, if it can be confirmed that the power supply from the power system 1 is not being performed normally and the charging / discharging device 20 and the power generation device 30 are connected to each other, that is, if it can be confirmed that the generated power of the power generation device 30 is not supplied to the power system 1, it can be said that the generated power of the power generation device 30 may be supplied to the charging / discharging device 20.

[0017] The present invention has been made in view of the above problems, and an object thereof is to provide a power supply system, a charging / discharging device, a power generation device, and a signal generation device that supply power from the power generation device as needed in a situation where the charging / discharging device and the power generation device are connected to each other.

Means for Solving the Problems

[0018] A characteristic configuration of a power supply system according to the present invention for achieving the above object is that a charging / discharging device, a power generation device, and a connection path between the charging / discharging device and the power generation device are switched to either a connection connection path in a state where the charging / discharging device and the power generation device are connected to each other and connected to a power system or an independent connection path in a state where the charging / discharging device and the power generation device are connected to each other and electrically disconnected from the power system. A power supply system comprising a connection switching unit. When the power supply from the power grid is in a normal state, the connection switching unit switches the connection path between the charge-discharge device and the power generation device to the linked connection path. When the power supply from the power grid is in an abnormal state where the power supply is not being carried out normally, the connection path between the charge-discharge device and the power generation device is configured to be switched to the self-sustaining connection path. The charge and discharge device is In the case of the abnormal state, a signal generation unit that outputs a self-sustaining signal to the voltage line constituting the self-sustaining connection path and does not output the self-sustaining signal in the case of the normal state is provided. The power generation device includes a signal detection unit connected to at least the voltage line constituting the self-sustaining connection path in the case of the abnormal state, and is configured to determine whether the signal detection unit has detected the self-sustaining signal. 、 When the remaining charge amount of the charge and discharge device is equal to or greater than a predetermined threshold and when it is less than the threshold, the signal generation unit makes the waveform of the self - supporting signal different. The power generation device is When the self - supporting signal detected by the signal detection unit indicates that the remaining charge amount of the charge and discharge device is equal to or greater than the threshold, the output power of the power generation device is adjusted to a value determined by a predetermined power supply determination rule. When the self - supporting signal detected by the signal detection unit indicates that the remaining charge amount of the charge and discharge device is less than the threshold, the output power of the power generation device is configured to be adjusted to a value equal to or greater than the value determined by the power supply determination rule. lies in the point. Here, the self-sustaining signal may be a waveform distinguishable from the waveform of the AC power supplied between the power generation device and the charge-discharge device. Also, the self-sustaining signal may be a signal of a specific frequency. Furthermore, the self-sustaining signal may be a signal including at least one of a change in the magnitude of the amplitude and a change in the level of the frequency. Moreover, the signal generation unit and the signal detection unit may include PLC devices.

[0019] According to the above characteristic configuration, in the case of an abnormal state where the power supply from the power grid is not being carried out normally, the signal generation unit of the charge and discharge device outputs a self - reliance signal to the voltage line constituting the self - reliance connection path, and in the normal state where the power supply from the power grid is being carried out normally, it does not output such a self - reliance signal. Further, the power generation device includes a signal detection unit connected to the voltage line constituting the self - reliance connection path. And the power generation device determines whether the signal detection unit is detecting a self - reliance signal. In this way, when the signal detection unit is detecting a self - reliance signal, the power generation device can operate after recognizing that power can be supplied to the charge and discharge device via the self - reliance connection path in a state where the power generation device and the charge and discharge device are electrically disconnected from the power grid. In addition, when the self - supporting signal detected by the signal detection unit indicates that the remaining charge amount of the power storage unit is equal to or greater than the threshold, that is, when it is confirmed that the charge and discharge device and the power generation device are connected to each other via the self - supporting connection path and are not connected to the power grid and the remaining charge amount of the power storage unit is equal to or greater than the threshold, the output power of the power generation device is adjusted to a value determined by a predetermined power supply determination rule. That is, even in an abnormal state where the power supply from the power grid is not normally performed, the output power of the power generation device can be supplied to the second load device group and the charge and discharge device via the self - supporting connection path. Also, when the self - supporting signal detected by the signal detection unit indicates that the remaining charge amount of the power storage unit is less than the threshold, that is, when it is confirmed that the charge and discharge device and the power generation device are connected to each other via the self - supporting connection path and are not connected to the power grid and the remaining charge amount of the power storage unit is less than the threshold, the output power of the power generation device is adjusted to a value equal to or greater than the value determined by the above - mentioned power supply determination rule. That is, even in an abnormal state where the power supply from the power grid is not normally performed, the output power of the power generation device can be supplied to the second load device group and the charge and discharge device via the self - supporting connection path so as to promote the increase in the remaining charge amount of the power storage unit of the charge and discharge device or suppress the decrease in the remaining charge amount. Therefore, it is possible to provide a power supply system that can supply power from the power generation device as needed under the situation where the charge and discharge device and the power generation device are connected to each other.

[0020] Another characteristic configuration of the power supply system according to the present invention is that, in the case of the normal state, the connection switching unit connects a first load device group including one or more power load devices and a second load device group including one or more power load devices not included in the first load device group to the associated connection path, and in the case of the abnormal state, the connection path between the charge and discharge device and the power generation device is switched so that the second load device group is connected to the self - reliance connection path.

[0021] According to the above characteristic configuration, in the normal state where the power supply from the power grid is being carried out normally, by the connection switching unit connecting the first load device group and the second load device group to the associated connection path, power can be supplied to the first load device group and the second load device group. Also, in the abnormal state where the power supply from the power grid is not being carried out normally, by the connection switching unit connecting the second load device group to the self - reliance connection path, power can be supplied to the second load device group.

[0022] Still another characteristic configuration of the power supply system according to the present invention is that in the case of the normal state, the connection switching unit connects a load device group including one or more power load devices to the interconnection path, and in the case of the abnormal state, the connection switching unit connects the load device group to the self-supporting connection path, thereby switching the connection path between the charge / discharge device and the power generation device.

[0023] According to the above characteristic configuration, in the normal state where the power supply from the power grid is being carried out normally, the connection switching unit can supply power to the load device group by connecting the load device group to the interconnection path. Also, in the abnormal state where the power supply from the power grid is not being carried out normally, the connection switching unit can supply power to the load device group by connecting the load device group to the self-supporting connection path.

[0028] A characteristic configuration of the charge / discharge device according to the present invention for achieving the above object lies in having the function of the charge / discharge device used in the power supply system.

[0029] According to the above characteristic configuration, it is possible to provide a charge / discharge device used in a power supply system that can supply power from the power generation device as needed under the situation where the charge / discharge device and the power generation device are connected to each other.

[0030] A characteristic configuration of the power generation device according to the present invention for achieving the above object lies in having the function of the power generation device used in the power supply system.

[0031] According to the above characteristic configuration, it is possible to provide a power generation device used in a power supply system that can supply power from the power generation device as needed under the situation where the charge / discharge device and the power generation device are connected to each other.

[0032] A characteristic configuration of the signal generation device according to the present invention for achieving the above object lies in having the function of the signal generation unit used in the power supply system.

[0033] According to the above-described characteristic configuration, it is possible to provide a signal generation device used in a power supply system that supplies power from a power generation device as necessary in a situation where a charge / discharge device and a power generation device are connected to each other.

Brief Description of the Drawings

[0034]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0035] <First Embodiment> Hereinafter, a power supply system according to a first embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the configurations of the first power supply system and the second power supply system will be described separately. In the drawings, the portions where power is supplied are drawn with thick lines.

[0036] 〔First Power Supply System〕 FIG. 1 is a diagram showing the configuration of a first power supply system. As shown in the figure, the first power supply system includes a charge / discharge device 20, a power generation device 30, and a connection switching unit 12. Specifically, a power line 2 is connected to a power grid 1. A power generation device 30 is connected to a first connection point P1 of the power line 2 via a first switching unit 13. A charge / discharge device 20 is connected to a second connection point P2 of the power line 2 via a second switching unit 14.

[0037] The charge / discharge device 20 includes a storage unit 21, a power conversion unit 22, and a charge / discharge control unit 23. In addition, the charge / discharge device 20 includes a signal generation unit 24 described later. And a signal generation device having the function of the signal generation unit 24 is realized. The storage unit 21 can be configured using a secondary battery such as a lithium-ion battery. The power conversion unit 22 can convert the power stored in the storage unit 21 into power with a desired voltage, frequency, and phase and output it. The charge / discharge control unit 23 controls the operation of the power conversion unit 22 to control the output power (discharge power) from the storage unit 21 and the input power (charge power) to the storage unit 21. Also, the power conversion unit 22 can detect the voltage and current of the power on the line to which the charge / discharge device 20 is connected.

[0038] The measurement result of a voltage measurement unit 9 that measures the voltage of the power on the power line 2 on the upstream side of the first connection point P1, that is, on the power grid 1 side, and the measurement result of a current measurement unit 10 that measures the current of the power on the power line 2 between the first connection point P1 and the second connection point P2 are transmitted to the charge / discharge device 20.

[0039] The voltage measurement unit 9 is configured using, for example, an instrument transformer used to measure the voltage value of electric power. Then, the charge / discharge control unit 23 of the charge / discharge device 20 refers to the measurement result of the voltage measurement unit 9 to determine whether it is a normal state in which the power supply from the power grid 1 is being carried out normally, or an abnormal state in which the power supply from the power grid 1 is not being carried out normally. The charge / discharge control unit 23 can determine whether the power supply from the power grid 1 is being carried out normally based on the voltage value of the electric power and the frequency of the electric power transmitted from the voltage measurement unit 9 and the like. For example, if the voltage value transmitted from the voltage measurement unit 9 is equal to or greater than a predetermined value, the charge / discharge control unit 23 determines that it is a normal state in which the power supply from the power grid 1 is being carried out normally, and if the voltage value transmitted from the voltage measurement unit 9 is less than the predetermined value, it can be determined that it is an abnormal state in which the power supply from the power grid 1 is not being carried out normally.

[0040] The current measurement unit 10 is configured using, for example, a current transformer (instrument current transformer) used to detect the current value of electric power. Then, the charge / discharge control unit 23 of the charge / discharge device 20 refers to the measurement result of the current measurement unit 10 to measure the electric power from the first connection point P1 to the second connection point P2. The charge / discharge control unit 23 can derive the power value from the product of the current value transmitted from the current measurement unit 10 and the measurement result of the voltage measurement unit 9 or a predetermined voltage value (for example, 100V, 200V, etc.). Then, the charge / discharge control unit 23 refers to the measurement result of the current measurement unit 10 to control the charging power or discharging power of the charge / discharge device 20.

[0041] When the power supply from the power grid 1 is in a normal state, the charge / discharge device 20 operates in the grid-connected operation mode, and when the power supply from the power grid 1 is in an abnormal state where the power supply is not being carried out normally, it operates in the self-sufficient operation mode. In the case of the grid-connected operation mode, the charge / discharge device 20, for example, refers to the measurement result of the current measurement unit 10 to control the charging power or discharging power so that the electric power from the first connection point P1 to the second connection point P2 becomes equal to the rated power generation of the power generation device 30. Also, in the case of the self-sufficient operation mode, the charge / discharge device 20, for example, controls the charging power or discharging power so as to maintain the voltage and frequency of the electric power in the self-sufficient connection path described later at predetermined values.

[0042] The power generation device 30 includes a power generation unit 31, a power conversion unit 32, a power consumption unit 33, and a power generation control unit 34. In addition, the power generation device 30 includes a signal detection unit 35, which will be described later. The power generation unit 31 is configured using, for example, a device including a fuel cell, or a device including an engine and a generator driven by the engine. The power conversion unit 32 can supply the power generated by the power generation device 30 as generated power converted into power with a desired voltage, frequency, and phase. Further, the power conversion unit 32 can detect the voltage and current of the line to which the power generation device 30 is connected.

[0043] The measurement result of the current measurement unit 11 that measures the current of the power of the power line 2 is transmitted to the power generation device 30 on the upstream side of the first connection point P1, that is, on the power system 1 side.

[0044] The current measurement unit 11 is configured using, for example, a current transformer (instrument current transformer) used to detect the current value of the power. Then, the power generation control unit 34 of the power generation device 30 measures the power from the power system 1 toward the first connection point P1 with reference to the measurement result of the current measurement unit 11. For example, the power generation control unit 34 can derive the power value from the product of the current value transmitted from the current measurement unit 11 and a predetermined voltage value (for example, 100V, 200V, etc.). Then, the power generation control unit 34 controls the generated power supplied from the power generation device 30 with reference to the measurement result of the current measurement unit 11.

[0045] When there is a voltage input to the line to which the power generation device 30 is connected, the power generation device 30 operates in the grid-connected operation mode or the islanded state mode, and when there is no such voltage input, it operates in the stand-alone operation mode. In the case of the grid-connected operation mode, the power generation device 30 controls the generated power to be supplied so that the power from the first connection point P1 toward the power system 1 becomes zero (that is, there is no reverse power flow), for example, with reference to the measurement result of the current measurement unit 11. Also, in the case of the stand-alone operation mode, the power generation device 30 supplies generated power equal to the load power in the stand-alone connection path described later, for example. The islanded state mode will be described later.

[0046] The connection switching unit 12 switches the connection path between the charging / discharging device 20 and the power generation device 30 to either a linked connection path in a state where the charging / discharging device 20 and the power generation device 30 are connected to each other and to the power grid 1, or an independent connection path in a state where the charging / discharging device 20 and the power generation device 30 are connected to each other and electrically disconnected from the power grid 1. Further, in the normal state, the connection switching unit 12 connects the general power load device 4 and the critical power load device 5 to the linked connection path, and in the abnormal state, switches the connection path between the charging / discharging device 20 and the power generation device 30 so as to connect the critical power load device 5 to the independent connection path.

[0047] A first load device group (general power load device 4) including one or more power load devices is connected to the second connection point P2 of the power line 2. The power supply system includes a first connection line 17 to which a second load device group (critical power load device 5) including one or more power load devices not included in the first load device group is connected. The power supply system also includes a second connection line 7. The general power load device 4 corresponds to the "first load device group including one or more power load devices" of the present invention, and the critical power load device 5 corresponds to the "second load device group including one or more power load devices not included in the first load device group" of the present invention.

[0048] The connection switching unit 12 of the present embodiment includes a first switching unit 13 and a second switching unit 14. The first switching unit 13 is provided between the power generation device 30 and the first connection point P1 of the power line 2. The second switching unit 14 is provided between the second connection point P2, the charging / discharging device 20, and the critical power load device 5.

[0049] The first switching unit 13 has a contact point a connected to the power generation device 30, a contact point b connected to the first connection point P1 of the power line 2, and a contact point c connected to the first connection line 17 via the second connection line 7. The contact point a of the first switching unit 13 is connected to the power conversion unit 32, the power consumption unit 33, and the signal detection unit 35 of the power generation device 30. And the first switching unit 13 is switched to either a state where the contact point a and the contact point b are connected or a state where the contact point a and the contact point c are connected.

[0050] The second switching unit 14 has a switch 14a and a switch 14b. The switch 14a switches between a state where contact point a and contact point b are connected and a state where contact point a and contact point c are connected. The switch 14b switches between a state where contact point a and contact point b are connected and a state where contact point a and contact point c are connected.

[0051] Contact point a of the switch 14a is connected to the charge / discharge device 20, contact point b of the switch 14a is connected to the second connection point P2 of the power line 2 and contact point c of the switch 14b, and contact point c of the switch 14a is connected to contact point b of the switch 14b. Contact point a of the switch 14b is connected to the critical power load device 5 and the second connection line 7 via the first connection line 17, contact point b of the switch 14b is connected to contact point c of the switch 14a, and contact point c of the switch 14b is connected to the second connection point P2 of the power line 2 and contact point b of the switch 14a.

[0052] The operation of the connection switching unit 12 is controlled by the charge / discharge control unit 23 of the charge / discharge device 20. Specifically, in the normal state where the power supply from the power grid 1 is being carried out normally by the connection switching unit 12, the charge / discharge control unit 23 switches the connection path between the charge / discharge device 20 and the power generation device 30 to the linked connection path, and in the abnormal state where the power supply from the power grid 1 is not being carried out normally, the charge / discharge control unit 23 is configured to switch the connection path between the charge / discharge device 20 and the power generation device 30 to the self-sustaining connection path.

[0053] The signal generation unit 24 and the signal detection unit 35 are realized using, for example, PLC (Power Line Communication) devices. Then, the signal generation unit 24 and the signal detection unit 35 as this PLC device are connected to the voltage lines constituting the above-described linked connection path and self-sustaining connection path, enabling the transmission and reception of the self-sustaining signal described later. The signal generation unit 24 outputs a self-sustaining signal to the voltage lines constituting the self-sustaining connection path in the abnormal state and does not output a self-sustaining signal in the normal state. The signal detection unit 35 is connected to at least the voltage lines constituting the self-sustaining connection path in the abnormal state.

[0054] FIG. 1 is a diagram showing an example when the power grid 1 is in a normal state in the power supply system. As shown in the figure, when the charge / discharge control unit 23 determines that the power grid 1 is in a normal state with reference to the measurement result of the voltage measurement unit 9, the first switching unit 13 is switched to a state where the contact a and the contact b are connected, and the switch 14a of the second switching unit 14 is switched to a state where the contact a and the contact b are connected, and the switch 14b of the second switching unit 14 is switched to a state where the contact a and the contact c are connected. As a result, the connection path between the charge / discharge device 20 and the power generation device 30 is switched to a tie connection path in a state where the charge / discharge device 20 and the power generation device 30 are connected to each other and connected to the power grid 1. That is, in the power supply system shown in FIG. 1, the tie connection path is set to a path connecting the power generation device 30, the first switching unit 13, the first connection point P1, the second connection point P2, the second switching unit 14, and the charge / discharge device 20. In this case, the general power load device 4 and the critical power load device 5 are also connected to the tie connection path and power is supplied.

[0055] FIG. 2 is a diagram showing an example when the power grid 1 is in an abnormal state in the power supply system. As shown in the figure, when the charge / discharge control unit 23 determines that the power grid 1 is in an abnormal state with reference to the measurement result of the voltage measurement unit 9, the first switching unit 13 is switched to a state where the contact a and the contact c are connected, and the switch 14a of the second switching unit 14 is switched to a state where the contact a and the contact c are connected, and the switch 14b of the second switching unit 14 is switched to a state where the contact a and the contact b are connected. As a result, the connection path between the charge / discharge device 20 and the power generation device 30 is switched to an independent connection path in a state where the charge / discharge device 20 and the power generation device 30 are connected to each other and electrically disconnected from the power grid 1. That is, in the power supply system shown in FIG. 2, the independent connection path is set to a path connecting the power generation device 30, the first switching unit 13, the second connection line 7, the first connection line 17, the second switching unit 14, and the charge / discharge device 20. In this case, the critical power load device 5 is connected to the independent connection path and power is supplied, but the general power load device 4 is electrically disconnected from the independent connection path and power is not supplied. Also, the signal generation unit 24 and the signal detection unit 35 are connected to the voltage line constituting the independent connection path.

[0056] However, there may be a case where the connection switching unit 12 does not operate normally. Although illustration is omitted, in the case of an abnormal state, the first switching unit 13 may connect the contact point a and the contact point b instead of the contact point a and the contact point c being connected as they should be. In this case, since the power generation device 30 and the charge / discharge device 20 are not connected, when the power generation device 30 supplies generated power, the power may be supplied to the power grid 1 side.

[0057] 〔Second power system〕 FIG. 3 and FIG. 4 are diagrams showing the configuration of the second power system. As shown in the figures, the second power system includes a charge / discharge device 20, a power generation device 30, and a connection switching unit 12. Specifically, the power line 2 is connected to the power grid 1. The charge / discharge device 20 is connected to the first connection point P1 of the power line 2 via a third switching unit 15. The power generation device 30 and the power load device 3 are connected to the second connection point P2 of the power line 2. The power load device 3 corresponds to the "load device group including one or more power load devices" of the present invention.

[0058] The charge / discharge device 20 is the same as the first power system described above, and includes a power storage unit 21, a power conversion unit 22, a charge / discharge control unit 23, and a signal generation unit 24. The measurement result of the voltage measurement unit 9 that measures the voltage of the power on the power line 2 on the upstream side of the first connection point P1, that is, on the power grid 1 side, and the measurement result of the current measurement unit 10 that measures the current of the power on the power line 2 on the upstream side of the first connection point P1 are transmitted to the charge / discharge device 20. Also, as will be described later, the charge / discharge device 20 includes a third switching unit 15. A noise prevention transformer unit 25 is provided between the third switching unit 15 and the signal generation unit 24.

[0059] The charge / discharge control unit 23 of the charge / discharge device 20 refers to the measurement result of the voltage measurement unit 9 to determine whether it is a normal state in which power supply from the power grid 1 is performed normally, or an abnormal state in which power supply from the power grid 1 is not performed normally.

[0060] The charge / discharge control unit 23 of the charge / discharge device 20 measures the power flowing from the power grid 1 towards the first connection point P1 with reference to the measurement result of the current measurement unit 10. When the charge / discharge device 20 is in a normal state where power supply from the power grid 1 is being carried out normally, it operates in the grid-connected operation mode. When it is in an abnormal state where power supply from the power grid 1 is not being carried out normally, it operates in the self-sustained operation mode. In the grid-connected operation mode, for example, the charge / discharge device 20 controls the charging power or discharging power with reference to the measurement result of the current measurement unit 10 so that the power flowing from the power grid 1 towards the first connection point P1 becomes zero. Also, in the self-sustained operation mode, the charge / discharge device 20 controls the charging power or discharging power, for example, to maintain the voltage and frequency of the power in the self-sustained connection path described later at predetermined values.

[0061] The power generation device 30 is the same as the above-described first power supply system, and includes a power generation unit 31, a power conversion unit 32, a power consumption unit 33, a power generation control unit 34, and a signal detection unit 35. The measurement result of the current measurement unit 11 that measures the current of the power on the power line 2 is transmitted between the fourth switching unit 16 and the second connection point P2 to the power generation device 30.

[0062] The power generation control unit 34 of the power generation device 30 measures the power flowing from the fourth switching unit 16 towards the second connection point P2 with reference to the measurement result of the current measurement unit 11. For example, the power generation control unit 34 can derive a power value from the product of the current value transmitted from the current measurement unit 11 and a predetermined voltage value (e.g., 100V, 200V, etc.). Then, the power generation control unit 34 controls the power generation power supplied from the power generation device 30 with reference to the measurement result of the current measurement unit 11.

[0063] When there is a voltage input to the line to which the power generation device 30 is connected, the power generation device 30 operates in the interconnected operation mode or the non-interconnected state mode, and when there is no such voltage input, it operates in the self-sustained operation mode. In the interconnected operation mode, the power generation device 30 controls the generated power to be supplied so that, for example, referring to the measurement result of the current measurement unit 11, the power flowing from the power grid 1 toward the first connection point P1 becomes zero (i.e., there is no reverse power flow). Also, in the self-sustained operation mode, the power generation device 30 supplies, for example, generated power equal to the load power in the self-sustained connection path described later. The non-interconnected state mode will be described later.

[0064] The connection switching unit 12 switches the connection path between the charge / discharge device 20 and the power generation device 30 to either the interconnected connection path in a state where the charge / discharge device 20 and the power generation device 30 are connected to each other and also connected to the power grid 1, or the self-sustained connection path in a state where the charge / discharge device 20 and the power generation device 30 are connected to each other and electrically disconnected from the power grid 1. Further, in the normal state, the connection switching unit 12 connects the power load device 3 to the interconnected connection path, and in the abnormal state, it switches the connection path between the charge / discharge device 20 and the power generation device 30 so as to connect the power load device 3 to the self-sustained connection path.

[0065] The connection switching unit 12 of the present embodiment includes a third switching unit 15 and a fourth switching unit 16. The third switching unit 15 is provided between the charge / discharge device 20 and the first connection point P1 of the power line 2. The fourth switching unit 16 is provided between the first connection point P1 and the second connection point P2 in the middle of the power line 2.

[0066] The third switching unit 15 has a contact point a connected to the power conversion unit 22 of the charge / discharge device 20, a contact point b connected to the first connection point P1 of the power line 2, and a contact point c connected to the fourth switching unit 16 via the noise prevention transformer unit 25 and the connection line 6. And the third switching unit 15 is switched to either a state where the contact point a and the contact point b are connected or a state where the contact point a and the contact point c are connected.

[0067] The fourth switching unit 16 has a contact point a connected to the second connection point P2 of the power line 2, that is, connected to the power load device 3 and the power generation device 30, a contact point b connected to the third switching unit 15 via the connection line 6 and the noise prevention transformer unit 25, and a contact point c connected to the first connection point P1 of the power line 2. And the fourth switching unit 16 is switched to either a state where the contact point a and the contact point b are connected or a state where the contact point a and the contact point c are connected.

[0068] The operation of the connection switching unit 12 is controlled by the charge and discharge control unit 23 of the charge and discharge device 20. Specifically, in the case of a normal state where power supply from the power grid 1 is being performed normally by the connection switching unit 12, the charge and discharge control unit 23 switches the connection path between the charge and discharge device 20 and the power generation device 30 to a linked connection path, and in the case of an abnormal state where power supply from the power grid 1 is not being performed normally, the charge and discharge control unit 23 is configured to switch the connection path between the charge and discharge device 20 and the power generation device 30 to a self - contained connection path.

[0069] FIG. 3 is a diagram showing an example when the power grid 1 is in a normal state in the second power system. As shown in the figure, when the charge and discharge control unit 23 determines that the power grid 1 is in a normal state with reference to the measurement result of the voltage measurement unit 9, the third switching unit 15 is switched to a state where the contact point a and the contact point b are connected, and the fourth switching unit 16 is switched to a state where the contact point a and the contact point b are connected. As a result, the connection path between the charge and discharge device 20 and the power generation device 30 is switched to a linked connection path in a state where the charge and discharge device 20 and the power generation device 30 are connected to each other and connected to the power grid 1. That is, in the power system shown in FIG. 3, the linked connection path is set to a path connecting the charge and discharge device 20, the third switching unit 15, the first connection point P1, the fourth switching unit 16, the second connection point P2, and the power generation device 30.

[0070] FIG. 4 is a diagram showing an example when the power system 1 is in an abnormal state in the second power system. As shown in the figure, when the charge / discharge control unit 23 determines that the power system 1 is in an abnormal state with reference to the measurement result of the voltage measurement unit 9, the third switching unit 15 is switched to a state where the contact point a and the contact point c are connected, and the fourth switching unit 16 is also switched to a state where the contact point a and the contact point c are connected. As a result, the connection path between the charge / discharge device 20 and the power generation device 30 is switched to a self - contained connection path in a state where the charge / discharge device 20 and the power generation device 30 are connected to each other and electrically disconnected from the power system 1. That is, in the power system shown in FIG. 4, the self - contained connection path is set to a path connecting the charge / discharge device 20, the third switching unit 15, the noise - preventing transformer unit 25, the connection line 6, the fourth switching unit 16, the second connection point P2, and the power generation device 30. Also, the signal generation unit 24 and the signal detection unit 35 are connected to the voltage lines constituting the self - contained connection path.

[0071] In addition, the connection switching unit 12 may not operate normally. Although not shown in the figure, in the case of an abnormal state, the fourth switching unit 16 may connect the contact point a and the contact point b instead of connecting the contact point a and the contact point c as it should be. In this case, since the power generation device 30 and the charge / discharge device 20 are not connected, when the power generation device 30 supplies generated power, there is a possibility that the power is supplied to the power system 1 side.

[0072] FIG. 5 is a flowchart for explaining the operation control of the charge / discharge device 20. In step #10, the charge / discharge control unit 23 determines whether the power system 1 is in a normal state with reference to the measurement result of the voltage measurement unit 9. Then, when the power system 1 is in a normal state, the charge / discharge control unit 23 proceeds to step #13 and operates the charge / discharge device 20 in the grid - connected operation mode, and when the power system 1 is in an abnormal state, the charge / discharge control unit 23 proceeds to step #11 and operates the charge / discharge device 20 in the self - contained operation mode.

[0073] In the case of the first power supply system, when the charge / discharge control unit 23 operates the charge / discharge device 20 in the linked operation mode, the connection switching unit 12 is switched to the state shown in FIG. 1, and when the charge / discharge device 20 is operated in the self-sustaining operation mode, the connection switching unit 12 is switched to the state shown in FIG. 2.

[0074] In the case of the second power supply system, when the charge / discharge control unit 23 operates the charge / discharge device 20 in the linked operation mode, the connection switching unit 12 is switched to the state shown in FIG. 3, and when the charge / discharge device 20 is operated in the self-sustaining operation mode, the connection switching unit 12 is switched to the state shown in FIG. 4.

[0075] In step #12, the charge / discharge control unit 23 continuously or at set timings transmits a predetermined self-sustaining signal from the signal generation unit 24 to the self-sustaining connection path while the power system 1 is determined to be in an abnormal state. The self-sustaining signal output by the signal generation unit 24 is pre-stored in a storage unit (not shown) of the charge / discharge device 20. In the present embodiment, the self-sustaining signal is, for example, a signal for indicating that the charge / discharge device 20 is operating in the self-sustaining operation mode.

[0076] The self-sustaining signal output by the signal generation unit 24 of the charge / discharge device 20 may be a signal distinguishable from the waveform of the AC power supplied between the power generation device 30 and the charge / discharge device 20, for example, a signal of a specific frequency. In other words, the self-sustaining signal is a signal including at least one of a change in the magnitude of the amplitude and a change in the level of the frequency. For example, the signal generation unit 24 continuously or at set timings outputs a voltage signal such as a sine wave with an amplitude of 12V and a frequency of 80Hz, or a voltage signal such as a square wave that continuously switches between a state of +5V and a state of -5V, for example, every 1 second. Alternatively, the signal generation unit 24 outputs, as the self-sustaining signal, a signal pattern representing a specific one or more characters (for example, a combination of a, b, c, d, etc.) in Morse code, continuously or at set timings.

[0077] The self - contained signal that the signal generation unit 24 of the charge - discharge device 20 is scheduled to output is stored in advance in the storage unit (not shown) of the power generation device 30. As a result, the power generation control unit 34 can determine whether the signal detection unit 35 has detected a predetermined signal such as the self - contained signal. Note that it may be the case where the self - contained signal is not stored in advance in the power generation device 30. In that case, when the power generation control unit 34 of the power generation device 30 detects a signal with a waveform or frequency different from that of the AC power waveform, it may determine that it is a self - contained signal.

[0078] Figure 6 is a flowchart for explaining the operation control of the power generation device 30. In step #20, the power generation control unit 34 determines whether there is a voltage input to the power generation device 30. For example, the power generation control unit 34 can determine whether there is a voltage input to the power generation device 30 by referring to the voltage detected by the power conversion unit 32. The case where there is no voltage input to the power generation device 30 means that no power is supplied from either the power grid 1 or the charge - discharge device 20. In that case, the power generation control unit 34 proceeds to step #28 and operates in the self - contained operation mode. For example, when the state of charge (SOC) of the charge - discharge device 20 is zero in the state shown in FIG. 2, no power is supplied to the power generation device 30 from either the power grid 1 or the charge - discharge device 20, but the generated power of the power generation device 30 operating in the self - contained operation mode is supplied to the critical power load device 5.

[0079] On the other hand, when there is a voltage input to the power generation device 30, that is, when power is supplied from at least one of the power grid 1 and the charge - discharge device 20, the power generation control unit 34 proceeds to step #21, changes the power consumption in the power consumption unit 33, and determines in step #22 whether the current flowing through the current measurement unit 11 changes.

[0080] For example, in the case of the first power supply system shown in FIGS. 1 and 2, if the power grid 1 is in a normal state, when the power consumption in the power consumption unit 33 is changed, the current measured by the current measurement unit 11 should change. On the other hand, if the power grid 1 is in an abnormal state, the current measured by the current measurement unit 11 should not change even if the power consumption in the power consumption unit 33 is changed.

[0081] In the case of the second power supply system shown in FIGS. 3 and 4, if the power grid 1 is in a normal state, when the power consumption at the power consumption unit 33 is changed, the current measured by the current measurement unit 11 should change. Also, even if the power grid 1 is in an abnormal state and power is being supplied from the charge / discharge device 20, when the power consumption at the power consumption unit 33 is changed, the current measured by the current measurement unit 11 should change.

[0082] Then, when the current flowing through the current measurement unit 11 does not change, the power generation control unit 34 proceeds to step #23. On the other hand, when the current flowing through the current measurement unit 10 changes, the power generation control unit 34 proceeds to step #30.

[0083] In step #23, the power generation control unit 34 stops the supply of generated power. That is, when the power consumption at the power consumption unit 33 is changed but the current measured by the current measurement unit 11 does not change, i.e., when it cannot be said that the power generation device 30 is connected to the normal-state power grid 1, this flowchart stops the supply of generated power from the power generation device 30.

[0084] Next, in step #24, the power generation control unit 34 determines whether the signal detection unit 35 has received a predetermined self-sustaining signal. Then, when the signal detection unit 35 has received the self-sustaining signal, the power generation control unit 34 proceeds to step #25, and when the signal detection unit 35 has not received the self-sustaining signal, it returns to the beginning of this flowchart while keeping the supply of generated power stopped, i.e., adjusting the output power to zero (step #26).

[0085] Step #25 assumes the case where the first power supply system is in the state shown in FIG. 2. In Step #25, when the signal detection unit 35 detects a self-sufficient signal, the power generation control unit 34 operates in an off-grid mode in which the output power of the power generation device 30 is adjusted to a value determined by a predetermined power supply determination rule. For example, in the first power supply system shown in FIG. 2, the power generation control unit 34 ignores the measurement result of the current measurement unit 11 and outputs a predetermined power such as 75% or 50% of the rated power generation as the power supply determination rule in the off-grid mode. As a result, after confirming that the charge / discharge device 20 and the power generation device 30 are connected to each other via the self-sufficient connection path, the power generation control unit 34 can supply the generated power to the critical power load device 5.

[0086] In Step #30, the power generation control unit 34 determines whether the signal detection unit 35 has received a predetermined self-sufficient signal. Then, when the signal detection unit 35 receives a self-sufficient signal, the power generation control unit 34 proceeds to Step #31 and operates in an off-grid mode in which the output power of the power generation device 30 is adjusted to a value determined by a predetermined power supply determination rule. Step #31 assumes the case where the second power supply system is in the state shown in FIG. 4. For example, in the second power supply system shown in FIG. 4, the power generation control unit 34 ignores the measurement result of the current measurement unit 11 and outputs a predetermined power such as 75% or 50% of the rated power generation as the power supply determination rule in the off-grid mode. Alternatively, in the second power supply system shown in FIG. 4, the power generation control unit 34 refers to the measurement result of the current measurement unit 11 and operates in an off-grid mode in which the power supply determination rule is to supply the generated power so that the power from the second connection point P2 to the fourth switching unit 16 is zero.

[0087] On the other hand, in Step #32, when the signal detection unit 35 has not received a self-sufficient signal, that is, when the second power supply system is in the state shown in FIG. 3, the power generation control unit 34 operates in the grid-connected operation mode.

[0088] <Second Embodiment> The power supply system of the second embodiment is different from the above embodiment in that a plurality of types of self - contained signals are used. The power supply system of the second embodiment will be described below, and the description of the same configuration as the above embodiment will be omitted.

[0089] In this embodiment, a plurality of distinguishable self - contained signals are stored in advance in a storage unit (not shown) of the charge - discharge device 20. For example, a self - contained signal for the signal generation unit 24 to output when the remaining charge amount of the power storage unit 21 is equal to or greater than a predetermined threshold value, and a self - contained signal for the signal generation unit 24 to output when the remaining charge amount of the power storage unit 21 is less than the above - mentioned threshold value are stored. Also, in a storage unit (not shown) of the power generation device 30, a plurality of self - contained signals that the signal generation unit 24 of the charge - discharge device 20 is scheduled to output are stored in advance. As a result, the power generation control unit 34 can determine whether the signal detected by the signal detection unit 35 is a self - contained signal output in a state where the remaining charge amount of the power storage unit 21 is equal to or greater than a predetermined threshold value, or a self - contained signal output in a state where the remaining charge amount of the power storage unit 21 is less than the above - mentioned threshold value.

[0090] Then, when the self - contained signal detected by the signal detection unit 35 of the power generation device 30 indicates that the remaining charge amount of the charge - discharge device 20 is equal to or greater than the above - mentioned threshold value, the output power of the power generation device 30 is adjusted to a value determined by a predetermined supply power determination rule. When the self - contained signal detected by the signal detection unit 35 indicates that the remaining charge amount of the charge - discharge device 20 is less than the above - mentioned threshold value, the output power of the power generation device 30 is configured to be adjusted to a value equal to or greater than the value determined by the above - mentioned supply power determination rule.

[0091] FIG. 7 is a flowchart for explaining the operation control of the charge - discharge device 20. In step #40, the charge - discharge control unit 23 refers to the measurement result of the voltage measurement unit 9 to determine whether the power grid 1 is in a normal state. Then, when the power grid 1 is in a normal state, the charge - discharge control unit 23 proceeds to step #45 and operates the charge - discharge device 20 in the grid - connected operation mode. When the power grid 1 is in an abnormal state, the charge - discharge control unit 23 proceeds to step #41 and operates the charge - discharge device 20 in the self - contained operation mode.

[0092] In the case of the first power supply system, when the charge / discharge control unit 23 operates the charge / discharge device 20 in the coordinated operation mode, the connection switching unit 12 is switched to the state shown in FIG. 1, and when the charge / discharge device 20 is operated in the self-sufficient operation mode, the connection switching unit 12 is switched to the state shown in FIG. 2.

[0093] In the case of the second power supply system, when the charge / discharge control unit 23 operates the charge / discharge device 20 in the coordinated operation mode, the connection switching unit 12 is switched to the state shown in FIG. 3, and when the charge / discharge device 20 is operated in the self-sufficient operation mode, the connection switching unit 12 is switched to the state shown in FIG. 4.

[0094] Next, in step #42, the charge / discharge control unit 23 determines whether the remaining charge amount of the power storage unit 21 is equal to or greater than a predetermined threshold value (for example, SOC = 80% etc.) stored in advance. Then, when the remaining charge amount is equal to or greater than the threshold value, the charge / discharge control unit 23 proceeds to step #43, and when the remaining charge amount is less than the threshold value, the charge / discharge control unit 23 proceeds to step #44.

[0095] In step #43, the charge / discharge control unit 23 continuously or at set timings transmits, from the signal generation unit 24, a self-sufficient signal predetermined for the case where the remaining charge amount of the power storage unit 21 is equal to or greater than the threshold value while the power grid 1 is determined to be in an abnormal state. In contrast, in step #44, the charge / discharge control unit 23 continuously or at set timings transmits, from the signal generation unit 24, a self-sufficient signal predetermined for the case where the remaining charge amount of the power storage unit 21 is less than the threshold value while the power grid 1 is determined to be in an abnormal state.

[0096] That is, the signal generation unit 24 makes the waveform of the self - contained signal different depending on whether the remaining charge amount of the power storage unit 21 is equal to or greater than a predetermined threshold value or less than the threshold value. For example, as an example of a self - contained signal predetermined for the case where the remaining charge amount of the power storage unit 21 is equal to or greater than the above - mentioned threshold value, a voltage signal having a waveform that continuously switches between a +5V state and a 0V state, for example, every second, is adopted. As a self - contained signal predetermined for the case where the remaining charge amount of the power storage unit 21 is less than the above - mentioned threshold value, a voltage signal having a waveform that continuously switches between a -5V state and a 0V state, for example, every second, can be adopted.

[0097] FIG. 8 is a flowchart for explaining the operation control of the power generation device 30. In step #50, the power generation control unit 34 determines whether there is a voltage input to the power generation device 30. For example, the power generation control unit 34 can determine whether there is a voltage input to the power generation device 30 by referring to the voltage detected by the power conversion unit 32. The case where there is no voltage input to the power generation device 30 means that no power is supplied from either the power grid 1 or the charge - discharge device 20. In that case, the power generation control unit 34 proceeds to step #59 and operates in the self - contained operation mode.

[0098] On the other hand, when there is a voltage input to the power generation device 30, that is, when power is supplied from at least one of the power grid 1 and the charge - discharge device 20, the power generation control unit 34 proceeds to step #51, changes the power consumption in the power consumption unit 33, and determines in step #52 whether the current flowing through the current measurement unit 11 changes.

[0099] Then, when the current flowing through the current measurement unit 11 does not change, the power generation control unit 34 proceeds to step #53. On the other hand, when the current flowing through the current measurement unit 11 changes, the power generation control unit 34 proceeds to step #60.

[0100] In Step #53, the power generation control unit 34 stops the supply of generated power. That is, if the current measured by the current measurement unit 11 does not change even when the power consumption of the power consumption unit 33 is changed, that is, if it cannot be said that the power generation device 30 is connected to the normal power grid 1, this flowchart stops the supply of generated power from the power generation device 30.

[0101] Next, in Step #54, the power generation control unit 34 determines whether the signal detection unit 35 has received a predetermined self - supporting signal. Then, when the signal detection unit 35 has received the self - supporting signal, the power generation control unit 34 proceeds to Step #55. When the signal detection unit 35 has not received the self - supporting signal, it returns to the beginning of this flowchart while keeping the supply of generated power stopped, that is, adjusting the output power to zero (Step #58).

[0102] In Step #55, when the received self - supporting signal indicates that the remaining charge of the power storage unit 21 is equal to or greater than the threshold value, the power generation control unit 34 proceeds to Step #56. When the received self - supporting signal indicates that the remaining charge of the power storage unit 21 is less than the threshold value, the power generation control unit 34 proceeds to Step #57.

[0103] In Step #56, the power generation control unit 34 operates in an off - grid mode in which the output power of the power generation device 30 is adjusted to a value determined by a predetermined power supply determination rule. For example, similar to that described in the first embodiment above, in the first power system shown in FIG. 2, the power generation control unit 34 ignores the measurement result of the current measurement unit 11 and operates in an off - grid mode with a predetermined power supply determination rule of outputting a predetermined power such as 75% or 50% of the rated power generation.

[0104] On the other hand, in step #57, the power generation control unit 34 operates in an off-grid state mode (with output power increase) that adjusts the output power of the power generation device 30 to a value equal to or greater than the value determined by the above supply power determination rule. For example, in the off-grid state mode (with output power increase), the power generation control unit 34 outputs power that is the same as or, for example, 100 W, 200 W, etc. higher than the value determined by the above supply power determination rule. As a result, it can be expected that the discharge power of the charge / discharge device 20 becomes small or the charge power becomes large, and the degree of increase in the remaining charge amount of the storage unit 21 of the charge / discharge device 20 becomes large or the degree of decrease becomes small.

[0105] Also, in step #60, the power generation control unit 34 determines whether the signal detection unit 35 has received a predetermined self-sufficient signal. Then, when the signal detection unit 35 has received a self-sufficient signal, the power generation control unit 34 proceeds to step #61, and when the signal detection unit 35 has not received a self-sufficient signal, the power generation control unit 34 proceeds to step #64 and operates in the grid-connected operation mode.

[0106] In step #61, when the received self-sufficient signal indicates that the remaining charge amount of the storage unit 21 is equal to or greater than the threshold value, the power generation control unit 34 proceeds to step #62, and when the received self-sufficient signal indicates that the remaining charge amount of the storage unit 21 is less than the threshold value, the power generation control unit 34 proceeds to step #63.

[0107] In step #62, the power generation control unit 34 operates in an off-grid state mode that adjusts the output power of the power generation device 30 to the value determined by a predetermined supply power determination rule. For example, in the second power supply system shown in FIG. 4, the power generation control unit 34 ignores the measurement result of the current measurement unit 11 and operates in an off-grid state mode with a supply power determination rule of outputting a predetermined power such as 75% or 50% of the rated power generation power. Alternatively, in the second power supply system shown in FIG. 4, the power generation control unit 34 refers to the measurement result of the current measurement unit 11 and operates in an off-grid state mode with a supply power determination rule of supplying power generation power so that the power from the second connection point P2 to the fourth switching unit 16 becomes zero.

[0108] On the other hand, in step #63, the power generation control unit 34 operates in an islanded mode (with output power increase) that adjusts the output power of the power generation device 30 to a value equal to or greater than the value determined by the supply power determination rule, similar to the case of step #57. For example, in the second power system shown in FIG. 4, in the islanded mode (with output power increase), the power generation control unit 34 outputs power that is the same as the value determined by the supply power determination rule or, for example, a predetermined value such as 100 W or 200 W greater. As a result, it can be expected that the discharge power of the charge / discharge device 20 becomes small or the charge power becomes large, and the degree of increase in the remaining charge amount of the power storage unit 21 of the charge / discharge device 20 becomes large or the degree of decrease becomes small.

[0109] <Another Embodiment> <1> In the above embodiment, specific examples have been given and described for the configurations of the power system, the charge / discharge device, the power generation device, and the signal generation device, but these configurations can be changed as appropriate. For example, FIGS. 1 and 2 show a state where the second switching unit 14 is configured separately from the charge / discharge device 20, but for example, the second switching unit 14 may be configured integrally with the charge / discharge device 20. Also, FIGS. 3 and 4 show a state where the third switching unit 15 is configured integrally with the charge / discharge device 20, but for example, the third switching unit 15 may be configured separately from the charge / discharge device 20.

[0110] <2> In the above embodiment, specific numerical values have been exemplified and described for the waveform examples of the self - contained signal, but these numerical values are described for illustrative purposes and can be changed as appropriate.

[0111] <3> In the above embodiment, specific examples have been given and described for the coordinated operation modes and the self - contained operation modes of the charge / discharge device 20 and the power generation device 30, and the islanded mode of the power generation device 30, but these are described for illustrative purposes and can be changed as appropriate.

[0112] <4> The configurations disclosed in the above embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with the configurations disclosed in other embodiments as long as there is no contradiction. Also, the embodiments disclosed in this specification are illustrative, and the embodiments of the present invention are not limited thereto, and can be appropriately modified within the scope not departing from the object of the present invention.

Industrial Applicability

[0113] The present invention can be used in a power supply system that supplies power from a power generation device as needed under the situation where a charge-discharge device and a power generation device are connected to each other.

Explanation of Reference Numerals

[0114] 1 Power grid 3 Power load device (load device group) 4 General power load device (first load device group) 5 Critical power load device (second load device group) 12 Connection switching unit 13 First switching unit (connection switching unit) 14 Second switching unit (connection switching unit) 15 Third switching unit (connection switching unit) 16 Fourth switching unit (connection switching unit) 20 Charge-discharge device 24 Signal generation unit 30 Power generation device 35 Signal detection unit

Claims

1. A power supply system comprising a connection switching unit that switches a connection path between a charge / discharge device, a power generation device, and a connection path between the charge / discharge device and the power generation device to either a linked connection path in a state where the charge / discharge device and the power generation device are connected to each other and connected to a power system or a self-sustaining connection path in a state where the charge / discharge device and the power generation device are connected to each other and electrically disconnected from the power system, wherein the connection switching unit is configured to switch the connection path between the charge / discharge device and the power generation device to the linked connection path in a normal state where power supply from the power system is being performed normally, and to switch the connection path between the charge / discharge device and the power generation device to the self-sustaining connection path in an abnormal state where power supply from the power system is not being performed normally, the charge / discharge device includes a signal generation unit that outputs a self-sustaining signal to a voltage line constituting the self-sustaining connection path in the abnormal state and does not output the self-sustaining signal in the normal state, the power generation device includes a signal detection unit connected to at least the voltage line constituting the self-sustaining connection path in the abnormal state, and is configured to determine whether or not the signal detection unit has detected the self-sustaining signal, the signal generation unit varies the waveform of the self-sustaining signal depending on whether the remaining charge amount of the charge / discharge device is equal to or greater than a predetermined threshold value or less than the threshold value, the power generation device, when the self-sustaining signal detected by the signal detection unit indicates that the remaining charge amount of the charge / discharge device is equal to or greater than the threshold value, adjusts the output power of the power generation device to a value determined by a predetermined power supply determination rule, and when the self-sustaining signal detected by the signal detection unit indicates that the remaining charge amount of the charge / discharge device is less than the threshold value, is configured to adjust the output power of the power generation device to a value equal to or greater than the value determined by the power supply determination rule.

2. The power supply system according to claim 1, wherein the connection switching unit connects, in the normal state, a first load device group including one or more power load devices and a second load device group including one or more power load devices not included in the first load device group to the linked connection path, and connects the second load device group to the self-sustaining connection path in the abnormal state, thereby switching the connection path between the charge / discharge device and the power generation device.

3. In the case of the normal state, the connection switching unit connects a load device group including one or more power load devices to the interconnection path, and in the case of the abnormal state, the connection switching unit connects the load device group to the self-supporting connection path, so as to switch the connection path between the charge and discharge device and the power generation device. The power supply system according to claim 1.

4. The self-supporting signal is a waveform distinguishable from the waveform of the AC power supplied between the power generation device and the charge and discharge device. The power supply system according to any one of claims 1 to 3.

5. The self-supporting signal is a signal having a specific frequency. The power supply system according to any one of claims 1 to 4.

6. The self-supporting signal is a signal including at least one of a change in amplitude magnitude and a change in frequency level. The power supply system according to any one of claims 1 to 5.

7. The signal generation unit and the signal detection unit include PLC devices. The power supply system according to any one of claims 1 to 6.

8. A charge and discharge device having the function of the charge and discharge device used in the power supply system according to any one of claims 1 to 7.

9. A power generation device having the function of the power generation device used in the power supply system according to any one of claims 1 to 7.

10. A signal generation device having the function of the signal generation unit used in the power supply system according to any one of claims 1 to 7.

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