Power interchange system and method for controlling power interchange system

Abstract

To satisfy a need for constantly interchanging electric power between power distribution communities.SOLUTION: A power interchange system (100) comprises a first battery (BT1) and a second battery (BT2) storing DC power, and a controller (CU0), and includes: a first power distribution community (C1) comprising a first DC-DC converter (DD5) that charges the batteries; and a second power distribution community (C2) comprising a second DC-DC converter (DD6) that receives the power from the batteries. The controller (CU0) performs control so that one of the batteries is discharged while the other of the batteries is being charged.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power interchange system between power distribution communities. [Background technology]

[0002] As shown in Patent Document 1, a power interchange system is being considered in which renewable energy sources such as solar power generation facilities, power storage devices, and electrical loads are combined into a single group (power distribution community), and self-generated and stored direct current electricity is exchanged between the groups.

[0003] In a power interchange system, DC power is exchanged between distribution communities by using independently deployed DC transmission and distribution equipment, rather than using transmission and distribution equipment managed by general electric utilities (power companies). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-161706 A Summary of the Invention [Problem to be solved by the invention]

[0005] The price of electricity purchased from general electric power companies increases progressively according to the amount of electricity used. Therefore, facilities that use large amounts of electricity are forced to put a brake on the amount of electricity they receive so that the amount does not increase.

[0006] Therefore, in the conventional technology described above, a power interchange system is used to interchange DC power between power distribution communities, so that the amount of received power does not increase relative to the amount of power used, thereby reducing the fee for received power.

[0007] However, in the conventional technology described above, since the power storage device cannot simultaneously charge and discharge, it is difficult to constantly exchange power between power distribution communities. Therefore, during periods when power exchange is not possible, it becomes necessary to purchase power from a general electric utility.

[0008] An object of one aspect of the present invention is to realize a power interchange system that extends the period during which power can be interchanged and enables the power required in a certain community to be instantly available. [Means for solving the problem]

[0009] In order to solve the above problem, a power interchange system according to one embodiment of the present invention is a power interchange system in which a first power distribution community and a second power distribution community are connected, the power interchange system includes a plurality of power storage devices including a first power storage device and a second power storage device that store DC power, and a control unit, the first power distribution community includes a first rectifier that rectifies received power to DC, a power generation device that generates power from renewable energy, a first electrical load that is a DC electrical load, a first DC power system to which the first rectifier, the power generation device, and the first electrical load are connected, and the plurality of power storage devices are connected to the first DC power system. the second power distribution community comprises a second rectifier that rectifies received power to DC, a second electrical load that is a DC electrical load, a second DC power system to which the second rectifier and the second electrical load are connected, and a DC receiving unit that at least receives power from the plurality of power storage devices to the second DC power system, and the control unit controls the DC power receiving unit to receive power from the second power storage device while the charging unit is charging the first power storage device, and controls the DC power receiving unit to receive power from the first power storage device while the charging unit is charging the second power storage device.

[0010] According to the above configuration, while the first power distribution community (charging unit) is constantly charging the power storage device, the second power distribution community (DC power receiving unit) can receive power from another power storage device that can discharge.

[0011] The second power distribution community may compare a contracted power in the second power distribution community with a load demand plan amount, which is a predicted value of the received power, and if the load demand plan amount exceeds the contracted power, the control unit may cause the DC power receiving unit to receive the DC power from the multiple power storage devices to the second power distribution community.

[0012] According to the above configuration, in the second power distribution community, the received power can be adjusted to be equal to or less than the contracted power by receiving power from the power storage device (power interchange).

[0013] The charging unit may charge the plurality of power storage devices using power generated by the power generation device.

[0014] According to the above configuration, the power storage device can be charged with free renewable energy.

[0015] When the amount of received power in a first period is expected to be greater than the amount of received power in a past second period corresponding to the first period, the received power may be reduced below the expected amount of received power in the first period.

[0016] According to the above configuration, the amount of received power can be controlled to be less than the previous amount.

[0017] The charging unit may charge the plurality of power storage devices using surplus DC power in the first DC power system.

[0018] According to the above configuration, the power storage device can be charged with surplus power.

[0019] The first power distribution community may further include an auxiliary battery that stores surplus DC power in the first DC power system, and the first power distribution community may compare the received power with a contracted power in the first power distribution community, and if the received power exceeds the contracted power, the control unit may cause the charging unit to charge the multiple power storage devices using the auxiliary battery.

[0020] According to the above configuration, since the first power distribution community includes the auxiliary battery, it is possible to adjust the received power so that it does not exceed the contracted power only in the first power distribution community. Also, the auxiliary battery can be used to charge the power storage device.

[0021] The power interchange system further includes a switching unit, The switching unit may have a first switching unit, a second switching unit, a third switching unit, and a fourth switching unit, and the control unit may control the switching unit to connect the charging unit and the first power storage device using the first switching unit and simultaneously connect the DC power receiving unit and the second power storage device using the fourth switching unit, and may also control the switching unit to connect the charging unit and the second power storage device using the second switching unit and simultaneously connect the DC power receiving unit and the first power storage device using the third switching unit.

[0022] According to the above configuration, the switching unit allows the DC power receiving unit to constantly receive power from the power storage device while the charging unit is constantly charging the power storage device.

[0023] The power interchange system further includes a third storage device and a power transmission unit, and the control unit may cause the power transmission unit to transmit the DC power stored in the first storage device and the second storage device to the third storage device, while simultaneously causing the DC receiving unit to receive the DC power from the third storage device to the second power distribution community, and may cause the DC receiving unit to transmit the DC power stored in the third storage device to the first storage device and the second storage device, while simultaneously causing the power transmission unit to receive the DC power from the first storage device and the second storage device to the first power distribution community.

[0024] According to the above configuration, power can be transmitted between the power storage devices, and therefore the second power distribution community can not only purchase power but also sell power.

[0025] The power interchange system may include at least one of the power storage devices and further include a plurality of transportation units that transport the power storage devices, and the control unit may cause the transportation units to transport at least one of the power storage devices from the first power distribution community to the second power distribution community.

[0026] According to the above configuration, a mobile power storage device can be used, and by transporting the power storage device, power can be exchanged even between power distribution communities where it is not possible to lay conductors.

[0027] In a control method for a power interchange system in which a first power distribution community and a second power distribution community are connected, the power interchange system includes a plurality of power storage devices including a first power storage device and a second power storage device that store DC power, the first power distribution community includes a first rectifier that rectifies received power to DC, a power generation device that generates power using renewable energy, a first electrical load that is a DC electrical load, a first DC power system to which the first rectifier, the power generation device, and the first electrical load are connected, and a charging unit that charges at least the plurality of power storage devices from the first DC power system, and the second power distribution community includes a first rectifier that rectifies received power to DC, a power generation device that generates power using renewable energy, a first electrical load that is a DC electrical load, a first DC power system to which the first rectifier, the power generation device, and the first electrical load are connected, and a charging unit that charges at least the plurality of power storage devices from the first DC power system, The community includes a second rectifier that rectifies the received power to DC, a second electrical load that is a DC electrical load, a second DC power system to which the second rectifier and the second electrical load are connected, and a DC receiving unit that at least receives power from the multiple power storage devices to the second DC power system, and the control method of the power interchange system includes a control step of controlling the DC power receiving unit to receive power from the second power storage device while the charging unit is charging the first power storage device, and controlling the DC power receiving unit to receive power from the first power storage device while the charging unit is charging the second power storage device.

[0028] In an electric power interchange system in which a first power distribution community and a second power distribution community are connected, the electric power interchange system includes a plurality of power storage devices including a first power storage device and a second power storage device that store DC power, and a control unit, and the first power distribution community includes a first rectifier that rectifies received power to DC, a power generation device that generates power using renewable energy, a first electrical load that is a DC electrical load, a first DC power system to which the first rectifier, the power generation device, and the first electrical load are connected, and a charging unit that charges at least the plurality of power storage devices from the first DC power system, and the control unit controls the second power storage device to transmit power to the second power distribution community while the charging unit is charging the first power storage device, and controls the first power storage device to transmit power to the second power distribution community while the charging unit is charging the second power storage device. Effect of the Invention

[0029] According to one aspect of the present invention, power can be exchanged between power distribution communities at all times. [Brief description of the drawings]

[0030] [Figure 1] 1 is a block diagram showing the configuration of a main part of a power interchange system. [Diagram 2] 4 is a table defining states of a power interchange device. [Diagram 3] 4 is a flowchart showing the operation of the power interchange system. [Figure 4] 13 is a graph showing the relationship between power in each part of the second power distribution community. [Diagram 5] 5 is a flowchart for calculating charging power for a first auxiliary battery. [Figure 6] 11 is a graph showing the relationship of power in each part of the first power distribution community when the first auxiliary battery is charging. [Figure 7] 5 is a flowchart for calculating the discharge power of a first auxiliary battery. [Figure 8]11 is a graph showing the relationship of power in each part of the first power distribution community when the first auxiliary battery is discharging. [Figure 9] 1 is a graph comparing the trends in the daily cumulative amount of electricity received in a given month and the previous month in the first electricity distribution community. [Figure 10] 1 is a block diagram showing the configuration of a main part of a power interchange system. [Figure 11] 1 is a block diagram showing the configuration of a main part of a power interchange system. [Figure 12] 1 is a block diagram showing the configuration of a main part of a power interchange system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] [Embodiment 1] Hereinafter, an embodiment of the present invention will be described in detail with reference to Fig. 1 to Fig. 9. Fig. 1 is a block diagram showing the configuration of a main part of a power interchange system 100. As shown in Fig. 1, the power interchange system 100 includes: a power supply unit 110;

[0032] (Outline of the power interchange system 100) In the power interchange system 100, power generated by the first distributed power source RE1, which is a renewable energy source, can be stored in the first battery BT1 and the second battery BT2 and used (power interchange) in the second power distribution community C2, which does not have an auxiliary battery. Therefore, even in the second power distribution community C2, which does not have an auxiliary battery, when the received power exceeds the contracted power and the power purchase cost from the general electric utility increases, the received power in the second power distribution community C2 can be reduced by power interchange. As a result, a reduction in the total power purchase cost can be expected.

[0033] (Configuration of power interchange system 100) The power interchange system 100 includes an AC power system AC, a first power distribution community C1, a second power distribution community C2, a power interchange device DC1, and a general control device CU0.

[0034] The AC power system AC is a power system for purchasing AC power from a general electric utility, and the first power distribution community C1 and the second power distribution community C2 each receive AC power. The AC power systems to be received may be the same system or different systems.

[0035] (Configuration of the first electricity distribution community C1) The first power distribution community C1 includes a first circuit breaker SW1, a first rectifier REC1, a plurality of first DC-DC (Direct Current - Direct Current) converters DD1 to DD4 and a first DC-DC converter DD5 (charging unit), a first distributed power source RE1 (power generation device), a first auxiliary battery SBT1 (auxiliary battery), a first electrical load LD1, a first electric vehicle EV1, and a first measurement and communication device CU1.

[0036] The first circuit breaker SW1 receives AC power from the AC power system AC, and cuts off the AC power when electrical work is being performed in the first power distribution community C1, when a ground fault occurs, or the like.

[0037] The first rectifier REC1 is a device that rectifies the AC power received by the first circuit breaker SW1 into DC power by diode rectification. Therefore, the first DC power system after the first rectifier REC1 becomes DC power. The DC power output by the first rectifier REC1 is P0.

[0038] The first DC-DC converters DD1 to DD5 are DC-DC converters connected to the first DC power system, converting the voltage of DC power and transmitting DC power between different voltages. In particular, the first DC-DC converter DD5 is a DC-DC converter that electrically connects the first DC power system of the first power distribution community C1 and the power interchange device DC1.

[0039] The first distributed power source RE1 is a power generating device that generates DC power from renewable energy and is connected to the first DC-DC converter DD1. A plurality of first distributed power sources RE1 may be provided and installed in different locations.

[0040] The first auxiliary battery SBT1 is a power storage device that stores DC power and is connected to the first DC-DC converter DD2.

[0041] The first electric load LD1 is a DC electric load that is connected to the first DC-DC converter DD3 and operates on DC power. The DC power may be converted to AC power by a DC-AC (Alternating Current - Direct Current) inverter to operate the AC electric load.

[0042] The first electric vehicle EV1 is an electric vehicle that is connected to a first DC-DC converter DD4, stores DC power, and runs on the DC power.

[0043] The first measurement and communication device CU1 measures the power of each part of the first power distribution community, communicates with the power interchange device DC1, and controls the DC-DC converters DD1-5 of each part based on the command of the power interchange device DC1. The measured power of each of the first DC-DC converters DD1-5 is P1-P5. Here, the direction of the current for P2 changes according to the charging and discharging of the auxiliary battery SBT1.

[0044] (Configuration of the second electricity distribution community C2) The second power distribution community C2 includes a second circuit breaker SW2, a second rectifier REC2, a plurality of second DC-DC converters DD6 (DC power receiving units) and a second DC-DC converter DD7, a second electric load LD2, and a second measurement and communication device CU2.

[0045] The second circuit breaker SW2 has a similar function in the second power distribution community C2 corresponding to the first circuit breaker SW1 of the first power distribution community C1.

[0046] The second rectifier REC2 has a similar function in the second power distribution community C2 to that of the first rectifier REC1 in the first power distribution community C1. The DC power output by the second rectifier REC2 is P8.

[0047] The second DC-DC converters DD6-7 have the same functions in the second power distribution community C2 as those corresponding to the first DC-DC converters DD1-5 in the first power distribution community C1. In particular, the second DC-DC converter DD6 corresponds to the first DC-DC converter DD5, and is a DC-DC converter that electrically connects the second DC power system in the second power distribution community C2 and the power interchange device DC1.

[0048] The second electric loads LD2 have a similar function in the second power distribution community C2 as the first electric loads LD1 in the first power distribution community C1, and may also include an electric vehicle electric load corresponding to the first electric vehicle EV1.

[0049] The second measurement and communication device CU2 has the same function in the second power distribution community C2 as the first measurement and communication device CU1 in the first power distribution community C1. The measured powers of the second DC-DC converters DD6-7 are P6-P7.

[0050] (Configuration of power interchange device DC1) The power interchange device DC1 includes a first battery BT1 (first power storage device), a second battery BT2 (second power storage device), switches SW00 (first switching unit), SW01 (second switching unit), SW10 (third switching unit), SW11 (fourth switching unit), and a switching control device CU3.

[0051] The first battery BT1 is a power storage device that stores DC power and is connected to the switches SW00 and SW01. The second battery BT2 is a power storage device that stores DC power and is connected to the switches SW10 and SW11.

[0052] The switches SW00 and SW10 are connected to the first DC-DC converter DD5 of the first power distribution community C1 and can be switched on or off based on a command from the switching control device CU3. The switches SW01 and SW11 are connected to the second DC-DC converter DD6 of the second power distribution community C2 and can be switched on or off based on a command from the switching control device CU3.

[0053] The switching control unit CU3 controls the switches SW00, SW01, SW10, and SW11 of each unit based on commands from the general control unit CU0.

[0054] (Configuration of the overall control device CU0) The overall control device CU0 (control unit) communicates with the first measurement and communication device CU1, the second measurement and communication device CU2, and the switching control device CU3, and controls each part of the power interchange system 100. Taking into consideration the power status of the first measurement and communication device CU1 and the power status of the second measurement and communication device CU2, the overall control device CU0 controls the switching control device CU3 to interchange power from the first power distribution community C1 to the second power distribution community C2.

[0055] (Status of power interchange unit DC1) The power interchange unit DC1 has two states. Figure 2 is a table that defines the states of the power interchange unit DC1.

[0056] 2, in state A, the switches SW00 and SW11 are ON, and the switches SW01 and SW10 are OFF. Therefore, the first power distribution community C1 is connected to the first battery BT1, and the second power distribution community C2 is connected to the second battery BT2. Therefore, while the first power distribution community C1 is charging the first battery BT1, the second power distribution community C2 can receive power from the second battery BT2.

[0057] Conversely, in state B, the switches SW00 and SW11 are OFF, and the switches SW01 and SW10 are ON. Therefore, the first power distribution community C1 is connected to the second battery BT2, and the second power distribution community C2 is connected to the first battery BT1. Therefore, while the first power distribution community C1 is charging the second battery BT2, the second power distribution community C2 can receive power from the first battery BT1.

[0058] In this way, by changing the logic of the switches SW00, SW01, SW10, and SW11 based on commands from the switching control device CU3, it is possible to change the charging and discharging states of the first battery BT1 and the second battery BT2.

[0059] In addition, since the first battery BT1 and the second battery BT2 can be charged and discharged simultaneously, for example, when the first battery BT1 is discharging and cannot discharge, the discharging operation is switched to the second battery BT2, and while the second battery BT2 is discharging, the first battery BT1 can be charged. Therefore, unlike Patent Document 1, charging and discharging can be performed at all times, and power interchange at all times is possible.

[0060] (Operation example of power interchange system 100) 3 is a flowchart showing the operation of the power interchange system 100. Furthermore, when explaining the operation example, mathematical expressions appear, but these mathematical expressions are substitution expressions in which the right side is substituted for the left side.

[0061] In S11, the operator turns on the power supply to the first power distribution community C1 and the second power distribution community C2.

[0062] In S12, the first measurement communication device CU1 measures P3, which is the power consumption of the first electric load LD1, and P4, which is the power consumption of the first electric vehicle EV1, calculates P3+P4, and transmits it to the general control device CU0. In addition, the first measurement communication device CU1 also transmits the remaining capacity (SOC: State Of Charge) of the first auxiliary battery SBT1 to the general control device CU0.

[0063] Here, the SOC of the first auxiliary battery SBT1 is an index that indicates the remaining percentage of the fully charged state of the power storage device minus the amount of electricity discharged. Repeated charging and discharging within a predetermined SOC range is important for extending the cycle life of the power storage device.

[0064] In S13, the overall control device CU0 determines whether the value of P3+P4 can be supplied from the first auxiliary battery SBT1. When making this determination, the overall control device CU0 determines whether the SOC of the first auxiliary battery SBT1 is within a predetermined range (for example, 20 to 80%).

[0065] If the SOC of the first auxiliary battery SBT1 is not within the predetermined range (No in S13), the process proceeds to S14. In S14, charging processing of the first auxiliary battery SBT1 is performed, and the charge amount of the first auxiliary battery SBT1 is calculated. The details of this process will be described later.

[0066] If the SOC of the first auxiliary battery SBT1 is within the predetermined range (Yes in S13), the process proceeds to S15. In S15, a discharge process of the first auxiliary battery SBT1 is performed, and the discharge amount of the first auxiliary battery SBT1 is calculated. This process will be described in detail later.

[0067] In S16, the first measurement and communication device CU1, based on a command from the overall control device CU0, causes the first DC-DC converter DD5 to transmit DC power from the first power distribution community C1 to the power interchange device DC1 to charge the first battery BT1 or the second battery BT2. At this time, based on a command from the overall control device CU0, the switching control device CU3 controls the switches SW00, SW01, SW10, and SW11 of each part to enable charging of the first battery BT1 or the second battery BT2.

[0068] In S17, the central control device CU0 calculates the planned amount of interchange supply from the power interchange device DC1 to the second power distribution community C2. As the planned amount of interchange supply, the most recent actual value of the amount of power supplied from the power interchange device DC1 to the second power distribution community C2 is adopted. Alternatively, the planned amount of interchange supply may be determined based on the actual value of the amount of power supplied from the power interchange device DC1 to the second power distribution community C2 during a certain previous period, using an actual average value or AI using pattern learning from the actual value.

[0069] In S18, the central control device CU0 calculates the load demand plan amount in the second power distribution community C2 based on the interchange supply plan amount. The load demand plan amount is an actual load value in the second power distribution community at that time. The load demand plan amount is calculated specifically as follows. Within a certain period (e.g., one day), the load power amount required in the future (e.g., the remaining period of today) in the second power distribution community C2 is estimated based on the actual value of the load power amount in the second power distribution community C2 in the previous period (e.g., the previous day). After that, the load demand plan amount is determined as the sum of the load power amount required in the second power distribution community C2 in the future and the load power amount in the second power distribution community in the certain period up to now (e.g., the period up to today). As a result, the load demand plan amount becomes the interchange supply plan amount immediately after.

[0070] In S19, the switching control device CU3 controls the switches SW00, SW01, SW10, and SW11 of each section based on a command from the general control device CU0 to enable discharging from the first battery BT1 or the second battery BT2.

[0071] Further, the second measurement and communication device CU2 interchanges power from the first battery BT1 or the second battery BT2 of the power interchange device DC1 to the second power distribution community C2 by the second DC-DC converter DD6 based on a command from the general control device CU0.

[0072] In S20, it is determined whether the planned amount of power supply is greater than the amount of power already supplied. If the planned amount of power supply is greater (Yes in S20), the planned amount of power supply has not yet been supplied, so the process returns to S19 to continue the power supply. If the planned amount of power supply is smaller (No in S20), the planned amount of power supply has been supplied, so the process proceeds to S21 to end the power supply.

[0073] In S21, the second measurement and communication device CU2 stops power interchange from the first battery BT1 or the second battery BT2 of the power interchange device DC1 to the second power distribution community C2 by the second DC-DC converter DD6 based on a command from the general control device CU0.

[0074] As described above, the second power distribution community C2 can make up for a power shortage by the power interchange from the power interchange device DC1. Fig. 4 is a graph showing the relationship of power in each part of the second power distribution community C2. As shown in Fig. 4 (C11), when the load demand plan amount of the second power distribution community C2 exceeds the contracted power P002, the actual received power of the second power distribution community C2 can be kept within the contracted power P002 by interchange of power.

[0075] (Calculation of charging power P2 of the first auxiliary battery SBT1) 5 is a flowchart for calculating the charging power P2 of the first auxiliary battery SBT1. Here, the power of the auxiliary battery SBT1 has a positive or negative sign depending on whether it is in a charging operation or a discharging operation, and is positive during the charging operation.

[0076] FIG. 6 is a graph showing the relationship of power among the parts of the first power distribution community C1 when the first auxiliary battery SBT1 is being charged.

[0077] First, consider the case where the remaining capacity of the first auxiliary battery SBT1 is less than a predetermined capacity (outside the control range) and charging is required.

[0078] In S31, the overall control device CU0 calculates a current required power P000. The required power P000 is the sum of the current charging power P2 of the auxiliary battery SBT1, the power consumption P3 of the first electric load LD1, and the power consumption P4 of the first electric vehicle EV1. In other words, the required power P000 is the power required for self-consumption in the first power distribution community.

[0079] P000=P2+P3+P4 In S32, the general control device CU0 determines whether the required power P000 is equal to or greater than the contracted power P001. If the required power P000 is less than the contracted power P001 (No in S32), the process proceeds to S33. If the required power P000 is equal to or greater than the contracted power P001 (Yes in S32), the process proceeds to S35.

[0080] In S33, the central control device CU0 determines that since the current required power P000 is less than the contracted power P001, it is still okay to receive power from the general electric power supplier. Therefore, the charging power P2 to the auxiliary battery SBT1 is maintained. Then, the received power P0 is calculated using the following formula. In other words, all of the power generated by the first distributed power source RE1 can be used to charge the first battery BT1 or the second battery BT2.

[0081] P0=P2+P3+P4=P000 In S34, the central control device CU0 determines that the generated power P1 of the first distributed power source RE1 can be entirely allocated to the discharged power P5 of the first power distribution community C1.

[0082] P5=P1 When the process proceeds from S33 to S34, the power of each part of the first power distribution community C1 shows the relationship shown in C21 in Fig. 6. That is, since the required power P000 is less than the contracted power P001, the power is supplied by receiving power from a general electric utility company and the auxiliary battery SBT1 is charged. Therefore, the charging power P2 of the auxiliary battery SBT1 is constant.

[0083] In S35, the central control device CU0 tries to reduce the amount of power purchased from the general electric power supplier as much as possible because the amount of power already received exceeds the contracted power. It judges whether there is any problem in reducing the charging power P2 of the auxiliary battery SBT1. The judgment is made based on the SOC value of the auxiliary battery SBT1, and whether the SOC value is within a predetermined management range (e.g., 20% or more). In other words, if the SOC value is within the predetermined management range, it is judged that there is no problem in discharging the battery and reducing the SOC value.

[0084] If it is OK to reduce the charging power P2 of the auxiliary battery SBT1 (Yes in S35), proceed to S36. If it is not OK to reduce the charging power P2 of the auxiliary battery SBT1 (No in S35), proceed to S37.

[0085] In S36, the central control device CU0 reduces the charging power P2 of the auxiliary battery SBT1 because the current required power P000 exceeds the contracted power P001 and the SOC of the auxiliary battery SBT1 is within the management range, and therefore the charging power P2 can be reduced. In other words, all of the power generated by the first distributed power source RE1 can be used to charge the first battery BT1 or the second battery BT2. Then, the central control device CU0 calculates the received power P0 using the following formula, and proceeds to S34.

[0086] P0=P2+P3+P4≠P000 When the process proceeds from S36 to S34, the power of each part of the first power distribution community C1 shows the relationship shown in C22 in Fig. 6. That is, since the required power P000 exceeds the contracted power P001, the system tries to charge the auxiliary battery SBT1 as much as possible while refraining from purchasing power from the general electric utility. As a result, the charging power P2 of the auxiliary battery SBT1 is reduced by the required power P000 that exceeds the contracted power P001.

[0087] In S37, the general control device CU0 attempts to maintain the charging power of the auxiliary battery SBT1 because the current required power P000 exceeds the contracted power P001 and the SOC of the auxiliary battery SBT1 is not within the management range. Therefore, the power shortage ΔP111 is supplied from the power interchange device DC1.

[0088] ΔP111=P2+P3+P4-P001=P000-P001 In S38, the central control device CU0 determines that the surplus power remaining after subtracting the power shortage ΔP111 from the generated power P1 of the first distributed power source RE1 can be used as the discharged power P5 of the first power distribution community C1.

[0089] P5=P1-ΔP111 When the process proceeds from S37 to S38, the power of each part of the first power distribution community C1 shows the relationship shown in C23 in Fig. 6. That is, since the required power P000 exceeds the contracted power P001, the system tries to charge the auxiliary battery SBT1 using the generated power P1 of the first distributed power source RE1 while refraining from purchasing power from the general electric power company as much as possible. Therefore, the charging power P2 of the auxiliary battery SBT1 is constant.

[0090] (Calculation of discharge power P2 of first auxiliary battery SBT1) 7 is a flowchart for calculating the discharge power P2 of the first auxiliary battery SBT1. Here, the power of the auxiliary battery SBT1 has a positive or negative sign in a charging operation and a discharging operation, and in a discharging operation, the sign is negative.

[0091] FIG. 8 is a graph showing the relationship of power among the parts of the first power distribution community C1 when the first auxiliary battery SBT1 is discharging.

[0092] Next, a case will be considered in which the first auxiliary battery SBT1 has a predetermined remaining capacity (within a control range), does not need to be charged, and can be discharged.

[0093] In S41, the overall control device CU0 determines whether the dischargeable power P200 of the first auxiliary battery SBT1 can cover the self-consumption P3+P4. That is, if the dischargeable power P200 exceeds the self-consumption P3+P4 (Yes in S41), the process proceeds to S42. Alternatively, if the discharge power P2 is less than the self-consumption P3+P4 (No in S41), the process proceeds to S44.

[0094] In S42, the overall control device CU0 makes the discharged power P2 of the first auxiliary battery SBT1 cover the self-consumption. Therefore, the relational expression is as follows.

[0095] P2=P3+P4 In S43, the central control device CU0 determines that the generated power P1 of the first distributed power source RE1 can be entirely allocated to the discharged power P5 of the first power distribution community C1.

[0096] P5=P1 When the process proceeds from S42 to S43, the power of each part of the first power distribution community C1 shows the relationship shown in C31 in Fig. 8. That is, the discharge power P2 of the first auxiliary battery SBT1 is the sum of the self-consumption P3+P4. Also, the received power P0 is 0.

[0097] In S44, the general control device CU0 judges whether or not to set the received power P0 to 0. The received power P0 may be set to 0 (no power reception) by the following process.

[0098] 9 (C41) is a graph comparing the transition of the daily accumulated amount of received power in a certain month (first period) and the previous month (second period) in the first power distribution community C1. The graph shows the accumulated amount of power in the previous month, the accumulated amount of power in this month, and the predicted accumulated amount in this month.

[0099] The accumulated energy amount for the previous month represents the accumulated amount of received energy up to the same day of the previous month. The accumulated energy amount for this month represents the amount of received energy up to that day in the case where a process to set the received energy to 0 (power management) is performed when it is determined that the amount of received energy up to that day in this month will exceed the amount of received energy up to the same day of the previous month. Note that the accumulated forecast for this month is the accumulated amount of energy up to that day in the case where the process to set the received energy to 0 is not performed.

[0100] Here, the determination is made according to the following formula:

[0101] This month's accumulated power consumption up to the previous day + Today's planned power consumption ≧ Previous month's accumulated power consumption up to the same day (1) This judgment formula judges whether or not the actual value of the accumulated power amount for the previous month up to that day will be exceeded when power is received on a certain day. Here, the planned power amount for today is the increment Δα of the predicted accumulated power amount for this month only for that day. If the planned power amount for today is large, the sum of the accumulated power amount for this month up to the previous day and the planned power amount for today will exceed the accumulated power amount for the previous month up to that day, and therefore if power is received on that day, it will represent that the received power will exceed that of the previous month, so it is judged that no power will be received on that day (P0=0).

[0102] Here, the case where daily calculations are performed and the current month and the previous month are compared on a monthly basis has been described, but this is not limited thereto. For example, a similar process may be performed on a weekly basis. Also, for example, if the first period is from December 1 to 24, 2020, in the above example, the second period is from November 1 to 24, 2020, which is the previous month, but is not limited thereto, and may be compared with the same period of the previous year, for example. That is, the second period may be from December 1 to 24, 2019.

[0103] If the judgment formula (1) is not satisfied (No in S44), the process proceeds to S45. If the judgment formula (1) is satisfied (Yes in S44), the process proceeds to S46.

[0104] In S45, the general control device CU0 calculates the received power P0 according to the following formula, and proceeds to S43.

[0105] P2=P200 P0=P3+P4+P2 When the process proceeds from S44 to S43, the power of each part of the first power distribution community C1 exhibits a relationship as shown in C32 in Fig. 8. That is, the total value of the self-consumption P3+P4 is covered by the total of the received power P0 and the discharged power P2 of the first auxiliary battery SBT1.

[0106] In S46, the central control device CU0 calculates that the self-consumption ΔP112 of the generated power P1 of the first distributed power source RE1 can be expressed by the following equation.

[0107] P2=P200 ΔP112=P3+P4+P2 In S47, the central control device CU0 determines that the surplus power P1 generated by the first distributed power source RE1 minus its self-consumption ΔP112 can be used to charge the first battery BT1 or the second battery BT2.

[0108] P5=P1-ΔP112 When the process proceeds from S46 to S47, the power of each part of the first power distribution community C1 shows the relationship shown in C33 in Fig. 8. That is, the total value of the self-consumption P3+P4 is covered by the sum of a part ΔP112 of the power generated by the first distributed power source and the discharged power P2 of the first auxiliary battery SBT1.

[0109] (Action and effect) As described above, in the present embodiment, the power interchange device DC1 including the first battery BT1 and the second battery BT2 alternately charges and always discharges by changing the connection states of the switches SW00, SW01, SW10, and SW11. That is, while the first battery BT1 is discharging, the second battery BT2 charges the second power distribution community C2, and while the second battery BT2 is discharging, the first battery BT1 charges. Therefore, the second power distribution community C2 can always receive power interchange in consideration of the relationship between the required power and the contracted power in the second power distribution community C2, that is, in a situation where the contracted power is exceeded, and the received power can be kept within the contracted power by the power interchange.

[0110] Furthermore, the first battery BT1 and the second battery BT2 can be charged using the generated power P1 of the first distributed power source RE1.

[0111] Furthermore, in the first power distribution community C1, when it is expected that the amount of received power in a first period, which is a predetermined period such as a month, will be greater than the amount of received power in a second period corresponding to the first period, the total amount of received power can be suppressed by reducing the amount of received power to be less than the amount of received power in the first period. When this measure is taken, the first auxiliary battery SBT1 is discharged instead of the received power to cover the power consumed by the home.

[0112] Similarly, a certain period (second period) from the previous time (e.g., the day before) is assumed to be the same period (first period) this time (e.g., the current day). If it is determined that the amount of received power in the first period exceeds the amount of received power in the second period, the general control device CU0 controls the amount of received power in the first period in a direction to reduce the amount of received power this time.

[0113] [Modifications] The power for charging the first battery BT1 and the second battery BT2 does not have to be limited to the generated power P1 of the first distributed power source RE1. That is, the first battery BT1 and the second battery BT2 may be charged using surplus DC power in the first DC power system, including the received power P0 in the first power distribution community C1. The surplus DC power in the first DC power system includes the generated power P1 of the first distributed power source RE1, the received power P0, and the discharged power P2 of the first auxiliary battery SBT1.

[0114] In the modified example, unlike the first embodiment, the first battery BT1 and the second battery BT2 can be stably charged regardless of the power generation status of the first distributed power source RE1. Therefore, when the second power distribution community C2 desires power interchange, the remaining capacity of both the first battery BT1 and the second battery BT2 decreases, and it is possible to reduce the risk of being unable to discharge.

[0115] [Embodiment 2] Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0116] 10 is a block diagram showing the configuration of a main part of a power interchange system 101. The power interchange system 101 differs from the power interchange system 100 in that it includes a second power distribution community C2b instead of the second power distribution community C2.

[0117] The second power distribution community C2b differs from the second power distribution community C2 in that it includes a second circuit breaker SW2, a second rectifier REC2, a plurality of second DC-DC converters DD6 and DD1b to DD3b, a second distributed power source RE2, a second auxiliary battery SBT2, a second electrical load LD2, and a second measurement and communication device CU2.

[0118] The second distributed power source RE2 has a function in the first power distribution community C1 similar to that of the first distributed power source RE1 of the first power distribution community C1.

[0119] The second auxiliary battery SBT2 has a function in the first power distribution community C1 similar to that of the first auxiliary battery SBT1 of the first power distribution community C1.

[0120] That is, the second power distribution community C2b includes distributed power sources and auxiliary batteries similar to the first power distribution community, and can respond to the power supply and demand situation within the second power distribution community C2b.

[0121] The present embodiment is different from the first embodiment in that the second power distribution community C2b can charge the first battery BT1 and the second battery BT2 when it can receive power from the first battery BT1 and the second battery BT2. Also, the first power distribution community C1 can receive power from the first battery BT1 and the second battery BT2 when it can charge from the first battery BT1 and the second battery BT2. That is, the first power distribution community C1 and the second power distribution community C2b can charge and discharge the first battery BT1 and the second battery BT, respectively, depending on the connection states of the switches SW00, SW01, SW10, and SW11 of the power interchange device DC1.

[0122] Therefore, in order for the first power distribution community C1 to also reduce the received power until it falls below the contracted power, it is possible to use not only the first auxiliary battery SBT1 but also the power interchange device DC1, making it easier to reduce the received power to within the contracted power.

[0123] [Embodiment 3] Other embodiments of the present invention are described below.

[0124] 11 is a block diagram showing the configuration of the main parts of the power interchange system 102. The power interchange system 102 differs from the power interchange system 101 in that it includes a power interchange device DC2 instead of the power interchange device DC1.

[0125] The power interchange device DC1 includes a first battery BT1, a second battery BT2, a third battery BT1b (third power storage device), a fourth battery BT2b (third power storage device), switches SW00, SW01, SW10, SW11, SW00b, SW01b, SW10b, SW11b, a third DC-DC converter DD9 (power transmission unit), and a switching control device CU3.

[0126] The third battery BT1b is a power storage device that stores DC power and is connected to the switches SW00b and SW01b. The fourth battery BT2b is a power storage device that stores DC power and is connected to the switches SW10b and SW11b.

[0127] The third battery BT1b and the fourth battery BT2b may be installed in a different location from the first battery BT1 and the second battery BT2 and may have a different owner. For example, the first battery BT1 and the second battery BT2 are facilities of the first power distribution community C1, and the third battery BT1b and the fourth battery BT2b are facilities of the second power distribution community C2b.

[0128] The third DC-DC converter DD9 is a DC-DC converter that connects the switches SW01 and SW11 and the switches SW01b and SW11b, converts the voltage of DC power, and transmits DC power between different voltages.

[0129] That is, power can be transmitted from the first battery BT1 and the second battery BT2 to the third battery BT1b and the fourth battery BT2b, or from the third battery BT1b and the fourth battery BT2b to the first battery BT1 and the second battery BT2. That is, the third DC-DC converter DD9 can exchange power between the batteries of the power exchange device DC2.

[0130] By performing power interchange between the batteries, the second power distribution community C2c can also sell power to the first power distribution community C1 in this embodiment, unlike the first embodiment. That is, in this embodiment, the power interchange makes it easy for both parties to adjust the received power to be equal to or less than the contracted power, and the power bill burden can be reduced.

[0131] [Embodiment 4] Other embodiments of the present invention are described below.

[0132] 12 is a block diagram showing the configuration of the main parts of the power interchange system 103. The power interchange system 103 differs from the power interchange system 100 in that it includes a power interchange device DC3 instead of the power interchange device DC1.

[0133] The power interchange device DC3 has a plurality of mobile power storage devices including a first mobile power storage device MBT1 (transport unit) and a second mobile power storage device MBT2 (transport unit) instead of a first battery BT1 and a second battery BT2, and does not have a switch or a switching control device.

[0134] The mobile power storage device is a mobile power storage device such as an electric vehicle equipped with a battery (power storage device) inside. The mobile power storage device moves between power distribution communities and transports power based on a command from the central control device CU0. That is, this embodiment differs from the other embodiments in that the medium for power interchange has changed from electrical wiring to a mobile power storage device.

[0135] A first mobile power storage device MBT1 is parked in a first power distribution community C1, and the first mobile power storage device MBT1 charges the power discharged from the first power distribution community C1. Meanwhile, a second mobile power storage device MBT2 is parked in a second power distribution community C2, and the second power distribution community receives the power discharged from the second mobile power storage device MBT2. Also, during this time, another third mobile power storage device MBT3 (transportation unit) may be present and transport power from the first power distribution community C1 to the second power distribution community C2.

[0136] The central control device CU0 checks the status of the first power distribution community C1 and the second power distribution community C2 and the status of the batteries of each mobile power storage device, and issues a movement command to exchange power.

[0137] In this embodiment, it is possible to simply exchange power while following the existing power system. In addition, since there is no need to lay conductors, there is also an advantage that power exchange is possible even when the first power distribution community C1 and the second power distribution community C2 are far apart.

[0138] [Software implementation example] The control blocks of the power interchange systems 100, 101, 102, 103 (particularly the general control device CU0, the first measurement and communication device CU1, the second measurement and communication device CU2, and the switching control device CU3) may be realized by logic circuits (hardware) formed in an integrated circuit (IC chip) or the like, or by software.

[0139] In the latter case, the power interchange systems 100, 101, 102, and 103 are provided with a computer that executes instructions of a program, which is software that realizes each function. The computer includes, for example, one or more processors, and a computer-readable recording medium that stores the program. The object of the present invention is achieved by the processor reading the program from the recording medium and executing it in the computer. The processor may be, for example, a CPU (Central Processing Unit). The recording medium may be a "non-transient tangible medium," such as a ROM (Read Only Memory), as well as a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like. The system may further include a RAM (Random Access Memory) in which the program is expanded. The program may be supplied to the computer via any transmission medium (such as a communication network or a broadcast wave) that can transmit the program. Note that one aspect of the present invention may also be realized in the form of a data signal embedded in a carrier wave, in which the program is embodied by electronic transmission.

[0140] [Additional Notes] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0141] 100, 101, 102, 103 Power interchange system AC alternating current power system BT1 First battery (first power storage device) BT2 Second battery (second power storage device) BT1b Third battery (third power storage device) BT2b Fourth battery (third power storage device) C1 First Distribution Community C2, C2b, C2c Second Distribution Community CU0 Overall control device (control unit) CU1 First measurement and communication device CU2 Second measurement and communication device CU3 Switching control unit DC1, DC2, DC3 power interchange device DD1~4 1st DC-DC converter DD5 1st DC-DC converter (charging section) DD6 Second DC-DC converter (DC power receiving section) DD7~8 Second DC-DC converter DD9 3rd DC-DC converter (power transmission section) EV1 First electric vehicle LD1 First Electric Load LD2 Second Electric Load MBT1 1st Mobile Power Storage Unit (Transportation Department) MBT2 Second Mobile Power Storage Unit (Transportation Section) MBT3 3rd Mobile Power Storage Unit (Transportation Department) P1 Power generation P2 charging power, discharging power P3, P4 power consumption P5 discharge power RE1 First distributed power source (power generation equipment) RE2 2nd distributed power source REC1 1st rectifier REC2 2nd rectifier SBT1 1st auxiliary battery (auxiliary battery) SBT2 Second auxiliary battery SW1 First circuit breaker SW2 Second circuit breaker SW00 Switch (first switching part) SW01 Switch (second switching part) SW10 Switch (third switching part) SW11 Switch (4th switching part) SW00b, SW01b, SW10b, SW11b switches

Claims

1. In a power interchange system in which a first power distribution community and a second power distribution community are connected, The power interchange system includes: a plurality of power storage devices including a first power storage device and a second power storage device that store DC power; A control unit, The first electricity distribution community: A first rectifier that rectifies the received power into direct current; A power generation device that generates power using renewable energy; a first electrical load which is a DC electrical load; a first DC power system to which the first rectifier, the power generation device, and the first electrical load are connected; a charging unit that charges at least the plurality of power storage devices from the first DC power system, The second electricity distribution community, A second rectifier that rectifies the received power into direct current; a second electrical load which is a DC electrical load; a second DC power system to which the second rectifier and the second electric load are connected; a DC power receiving unit that receives at least power from the plurality of power storage devices to the second DC power system, The control unit controls the DC power receiving unit to receive power from the second power storage device while the charging unit is charging the first power storage device, and controls the DC power receiving unit to receive power from the first power storage device while the charging unit is charging the second power storage device.

2. The second power distribution community compares a contracted power in the second power distribution community with a load demand plan amount, which is a predicted value of the received power, and if the load demand plan amount exceeds the contracted power, The power interchange system according to claim 1 , wherein the control unit causes the DC power receiving unit to receive the DC power from the plurality of power storage devices to the second power distribution community.

3. The power interchange system according to claim 1 or 2, wherein the charging unit charges the plurality of power storage devices using power generated by the power generation device.

4. 4. The power interchange system according to claim 1, wherein, when it is expected that the amount of power received by the first power distribution community in a first period will be greater than the amount of power received by the first power distribution community in a past second period corresponding to the first period, the amount of power received by the first power distribution community is reduced below the expected amount of power received in the first period.

5. The power interchange system according to claim 1 , wherein the charging unit charges the plurality of power storage devices using the received power.

6. the first power distribution community further includes an auxiliary battery that stores excess DC power in the first DC power system; The first power distribution community compares the contracted power in the first power distribution community with the received power, and if the received power exceeds the contracted power, The power interchange system according to claim 1 , wherein the control unit causes the charging unit to charge the plurality of power storage devices using the auxiliary battery.

7. The power interchange system further includes a switching unit, The switching unit includes a first switching unit, a second switching unit, a third switching unit, and a fourth switching unit, 7. The power interchange system according to any one of claims 1 to 6, wherein the control unit controls the switching unit to connect the charging unit and the first storage device using the first switching unit while simultaneously connecting the DC receiving unit and the second storage device using the fourth switching unit, and controls the switching unit to connect the charging unit and the second storage device using the second switching unit while simultaneously connecting the DC receiving unit and the first storage device using the third switching unit.

8. The power interchange system further includes a third power storage device and a power transmission unit, 8. The power interchange system of claim 7, wherein the control unit causes the power transmitting unit to transmit the DC power stored in the first storage device and the second storage device to the third storage device, while simultaneously causing the DC receiving unit to receive the DC power from the third storage device to the second power distribution community, and causes the DC receiving unit to transmit the DC power stored in the third storage device to the first storage device and the second storage device, while simultaneously causing the power transmitting unit to receive the DC power from the first storage device and the second storage device to the first power distribution community.

9. The power interchange system includes at least one of the power storage devices and further includes a plurality of transport units that transport the power storage devices; The power interchange system according to claim 1 , wherein the control unit causes the transport unit to transport at least one of the power storage devices from the first power distribution community to the second power distribution community.

10. A method for controlling a power interchange system in which a first power distribution community and a second power distribution community are connected, comprising: the power interchange system includes a plurality of power storage devices including a first power storage device and a second power storage device that store DC power; The first electricity distribution community: A first rectifier that rectifies the received power into direct current; A power generation device that generates power using renewable energy; a first electrical load which is a DC electrical load; a first DC power system to which the first rectifier, the power generation device, and the first electrical load are connected; a charging unit that charges at least the plurality of power storage devices from the first DC power system, The second electricity distribution community, A second rectifier that rectifies the received power into direct current; a second electrical load which is a DC electrical load; a second DC power system to which the second rectifier and the second electric load are connected; a DC power receiving unit that receives at least power from the plurality of power storage devices to the second DC power system, The control method for the power interchange system includes: A control method for a power interchange system including a control step of controlling the DC power receiving unit to receive power from the second power storage device while the charging unit is charging the first power storage device, and controlling the DC power receiving unit to receive power from the first power storage device while the charging unit is charging the second power storage device.

Images