Energy storage power conditioner and energy storage system

Abstract

To improve degree-of-freedom of a system configuration including a power storage power conditioner.SOLUTION: A power storage power conditioner comprises: an input part into which a DC power is input; a first transformation part; a first input / output part in which the DC power transformed by the first transformation part is output to a storage battery unit and into which the DC power is input from the storage battery unit; a conversion part that converts the DC power into an AC power; a second input / output part in which the AC power obtained by conversion by the conversion part is output to an electric power system or a load, and into which the AC power is input from the electric power system; a first control part; and a first communication part. The DC power input into the input part and the DC power input into the second input / output part and converted by the conversion part are input into the first transformation part. The DC power output from the first transformation part and the DC power input into the input part are input into the conversion part. The first control part transmits, to the storage battery unit, a command in which a response corresponding to a characteristic of the storage battery unit is determined, and controls an output of the first transformation part or the conversion part based on the response of the storage battery unit.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a power storage power conditioner and a power storage system. [Background technology]

[0002] 2. Description of the Related Art Conventionally, a power conditioner is known that boosts the voltage of DC power obtained by PV (photovoltaic power generation) using a DC / DC converter, converts this DC power to AC power, and outputs it to a power grid.

[0003] In addition, hybrid power conditioners that convert DC power generated by PV into AC power and supply it to a load and / or a power grid, while also charging surplus power into a storage battery unit, have also been put into practical use (see, for example, Patent Document 1).

[0004] Here, in the conventional power conditioner as described above, control is performed according to the rated capacity of the storage battery unit, and sufficient consideration is not given to improving the degree of freedom of the system including the power conditioner. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2012-222908 A Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a technology that can improve the flexibility of system configuration including a storage power conditioner connected to a storage battery unit. [Means for solving the problem]

[0007] To solve the above problems, the present invention provides: an input unit to which DC power is input; A first transformer unit that transforms a voltage of the DC power; a first input / output unit that outputs the DC power transformed by the first transformer unit to a storage battery unit and receives the DC power from the storage battery unit; A converter for converting DC power into AC power; a second input / output unit that outputs the AC power converted by the conversion unit to a power system or a load and receives AC power from the power system; A first control unit that controls the first transformer unit and the converter unit; A first communication unit that communicates with the storage battery unit; Equipped with The first transformer receives the DC power input to the input unit and the DC power input to the second input / output unit and converted by the conversion unit, The converter receives the DC power output from the first transformer and the DC power input to the input unit, The first control unit is a storage power conditioner characterized in that it transmits a command, in which a response corresponding to the characteristics of the storage battery unit is defined, to the storage battery unit via the first communication unit, and controls the output of the first transformer unit or the conversion unit depending on the response of the storage battery unit to the command.

[0008] According to the present invention, the first control unit of the storage power conditioner can recognize the characteristics of the storage battery unit by transmitting a command, in which a response corresponding to the characteristics of the storage battery unit is defined, to the storage battery unit via the first communication unit and receiving the response of the storage battery unit to the command. By controlling the output of the first transformer or converter of the storage power conditioner according to the characteristics of the storage battery unit recognized in this manner, a system can be configured by connecting storage battery units having various characteristics to the storage power conditioner. Therefore, it is possible to improve the degree of freedom in the configuration of a system including a storage power conditioner. An example of such a characteristic of the storage battery unit is rated capacity, but is not limited to this.

[0009] In addition, in the present invention, The first control unit may be configured to determine that an abnormality has occurred when the first communication unit does not receive a response from the storage battery unit within a predetermined time for any command sent to the storage battery unit.

[0010] According to this, when a storage battery unit that does not have the preset characteristics is connected, the first control unit of the storage power conditioner determines that an abnormality has occurred, making it possible to also deal with storage battery units that do not have the preset characteristics.

[0011] In addition, in the present invention, The characteristic of the storage battery unit may be a rated capacity of the storage battery unit.

[0012] According to this, by controlling the output of the first transformer of the storage power conditioner according to the recognized rated capacity of the storage battery unit, it is possible to configure a system by connecting storage battery units having various rated capacities to the storage power conditioner, thereby improving the degree of freedom in the configuration of a system including a storage power conditioner.

[0013] In addition, in the present invention, a first power value acquisition unit that acquires a DC power value input to the input unit, and a second power value acquisition unit that acquires an AC power value output from the second input / output unit to the load, The first transformer transforms a voltage of the DC power input to the input unit, The conversion unit converts the DC power input to the input unit into AC power, The first control unit may be configured to control the first transformer unit in accordance with the rated capacity of the storage battery unit based on a DC power value input to the input unit and an AC power value output from the second input / output unit to the load.

[0014] According to this, based on the DC power value input to the input unit and the AC power value output from the second input / output unit to the load, the first control unit controls the first transformer unit according to the rated capacity of the battery unit. Therefore, giving priority to the power supply to the load, the charge and discharge of the battery unit can be performed according to the DC power value input to the input unit.

[0015] Also, in the present invention, when the DC power value input to the input unit is P1 and the AC power value output from the second input / output unit to the load is P2, the first control unit charges the battery unit with the DC power input to the input unit according to the rated capacity when P1 > P2, when P1 < P2, inputs the DC power discharged from the battery unit together with the DC power input to the input unit to the conversion unit, and outputs the converted AC power from the second input / output unit to the load.

[0016] According to this, the AC power obtained by converting the DC power input to the input unit is preferentially supplied to the load. When there is surplus power, the battery unit is charged. When the power supplied by only the DC power input to the input unit is insufficient for the load, the battery unit can be discharged to increase the power supplied to the load. Therefore, power can be stably supplied to the load.

[0017] Also, the present invention includes the battery power conditioner, a second transformer unit that transforms the DC power generated by the power generation device, an output unit that outputs the DC power output from the second transformer unit to the input unit, a second control unit that controls the second transformer unit, a power value measurement unit that measures the power value of the DC power output from the output unit to the input unit, and a second communication unit that communicates with the battery power conditioner. The power storage system includes a transformer device having these components, and is a power storage system comprising The second control unit is characterized in that it transmits the power value of the DC power measured by the power value measuring unit from the second communication unit to the first control unit serving as the first power value acquiring unit.

[0018] According to this, DC power generated by the power generation device is transformed by the transformer device and input to an input unit of the power storage power conditioner. The DC power value input to the input unit is measured by a power value measuring unit of the transformer device and transmitted to a first control unit of the power storage power conditioner via the second communication unit and the first communication unit. Since the power value measured by the power value measuring unit of the transformer device can be acquired in the power storage power conditioner, in a power storage system including the power generation device, the transformer device, and the power storage power conditioner, power supply to a load is prioritized, and charging and discharging of the storage battery unit can be performed according to the DC power value input to the input unit from the power generation device and the transformer device. In addition, the AC power converted from the DC power input to the input section from the power generation device and the transformer device is supplied to the load with priority, and when there is surplus power, the battery unit is charged, and when the power supplied to the load is insufficient with only the DC power input to the input section, the battery unit is discharged to increase the power supplied to the load. Therefore, power can be stably supplied to the load. Effect of the Invention

[0019] According to the present invention, it is possible to improve the degree of freedom in the system configuration including a storage power conditioner connected to a storage battery unit. [Brief description of the drawings]

[0020] [Figure 1] 1 is a block diagram showing an example of a power storage system according to an embodiment of the present invention. [Diagram 2] 1 is a diagram showing an overall configuration of a power storage system according to an embodiment of the present invention; [Diagram 3] 1 is a flowchart showing a procedure of a recognition process of a rated capacity according to an embodiment of the present invention. [Figure 4]4 is a flowchart showing a procedure of charge / discharge control according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] [Application example] Hereinafter, application examples of the present invention will be described with reference to the drawings. 1 is a diagram showing an example of a power storage system 1 including a power storage power conditioner 4 according to an application example of the present invention. The power storage system 1 includes a power generation device 2, a transformer device 3, the power storage power conditioner 4, and a storage battery unit 5.

[0022] The power generation device 2 is a device capable of generating power. The power generation device 2 inputs the generated DC power to the transformer device 3. The transformer device 3 has an input unit 31, a transformer unit 32, an output unit 33, a control unit 34, and a communication unit 35. The transformer unit 32 transforms the DC power input to the input unit 31. The transformer unit 32 is an example of a second transformer unit of the present invention. The output unit 33 inputs the transformed DC power to the storage power conditioner 4. The control unit 34 controls the transformer unit 32. The control unit 34 is an example of a second control unit of the present invention. The control unit 34 has an output power measurement unit 341 that measures a power value (DC power value) of the DC power output to the input unit 41 from a current value of the DC power output from the output unit 33 and an output voltage value of the transformer unit 32, which are measured by the CT 3411. The output power measuring unit 341 is an example of a power value measuring unit of the present invention. The control unit 34 has a processor such as a CPU or an MPU and a memory such as a RAM or a ROM. The communication unit 35 communicates with the storage power conditioner 4 via a wired or wireless connection. The communication unit is an example of a second communication unit of the present invention.

[0023] The storage power conditioner 4 has an input unit 41, a transformer unit 42, an input / output unit 43, a conversion unit 44, an input / output unit 45, a control unit 46, and a communication unit 47. The DC power output from the output unit 33 of the transformer device 3 is input to the input unit 41. The transformer unit 42 transforms the voltage of the DC power input to the input unit 41. The transformer unit 42 is an example of a first transformer unit of the present invention. The input / output unit 43 inputs the transformed DC power to the storage battery unit 5. In addition, the DC power output from the storage battery unit 5 is input to the input / output unit 43. The input / output unit 43 is an example of a first input / output unit of the present invention. The transformer unit 42 transforms the voltage of the DC power input to the input / output unit 43 and outputs it. The conversion unit 44 converts the DC power output from the transformer unit 42 into AC power. The input / output unit 45 outputs the AC power to the power system 6 or the load 7. The input / output unit 45 is an example of a second input / output unit of the present invention. The input / output unit 45 is provided with an output power measurement unit 451 that measures the power value (AC power value) of the AC power output from the conversion unit 44 via the input / output unit 45. The output power measurement unit 451 is an example of a second power value acquisition unit of the present invention. The AC power output from the power system 6 is input to the input / output unit 45. The conversion unit 44 converts the AC power input to the input / output unit 45 into DC power and outputs it. The transformer unit 42 transforms the voltage of the DC power output from the conversion unit 44. The control unit 46 controls the transformer unit 42 and the conversion unit 44. The control unit 46 is an example of a first control unit of the present invention. The control unit 46 has a processor such as a CPU or an MPU and a memory such as a RAM or a ROM. The communication unit 47 communicates with the storage battery unit 5 and the transformer device 3 via a wired or wireless connection. The information received from the storage battery unit 5 and the transformer device 3 is transmitted to the control unit 46. The communication unit 47 is an example of a first communication unit of the present invention.

[0024] The storage battery unit 5 is a rechargeable secondary battery.

[0025] The storage power conditioner 4 automatically recognizes the rated capacity, which is an example of the characteristics of the storage battery unit 5 connected thereto, and controls charging and discharging of the storage battery unit 5 based on the recognized rated capacity. The automatic recognition process of the rated capacity of the storage battery unit 5 will be described with reference to the flowchart of FIG. 3. In this case, storage battery units with three types of rated capacity, 6.5 kWh, 9.8 kWh, and 16.4 kWh, are set in advance as candidates for the storage battery unit 5 to be connected to the storage power conditioner 4. For the automatic recognition of the rated capacity of the storage battery unit 5, an Initialize command including identification information called a Fixed Number assigned to each type of storage battery unit 5 is used. The control unit 46 of the storage power conditioner 4 transmits the Initialize command including the Fixed Number assigned to each type of storage battery unit 5 to the storage battery unit 5 via the communication unit 47 in the order of 6.5 kWh, 9.8 kWh, and 16.4 kWh (steps S1, S4, and S8). When the storage battery unit 5 receives an Initialize command that includes its own fixed number, it returns a normal response, and when it receives an Initialize command that does not include its own fixed number, it returns an abnormal response or does not return a response. The control unit 46 determines that the rated capacity of the storage battery unit 5 is the rated capacity corresponding to the fixed number, and stores the determination result (steps S3, S7, and S11). If the control unit 46 receives an abnormal response via the communication unit 47 or does not receive a response within a predetermined time, it transmits an Initialize command including the next fixed number in sequence. If an abnormal response is returned to all of the Initialize commands including the fixed numbers corresponding to 6.5 kWh, 9.8 kWh, and 16.4 kWh, or if no response is received within a predetermined time, it determines that there is a storage battery connection abnormality (step S12).

[0026] By controlling the output of the transformer unit 42 according to the rated capacity recognized in this manner, it is possible to perform appropriate charge / discharge control without damaging the storage battery units 5. In other words, storage battery units 5 having a plurality of types of rated capacities can be connected to the storage power conditioner 4, enabling operation according to different rated capacities, and improving the degree of freedom in the configuration of the storage system 1 including the storage power conditioner 4.

[0027] Example 1 In the following, a power storage system 1 according to an embodiment of the present invention will be described in more detail with reference to the drawings. However, the configurations of the devices and systems described in the embodiments should be appropriately modified depending on various conditions. In other words, the scope of the present invention is not limited to the following embodiments.

[0028] <System configuration> 1 is a block diagram showing a schematic configuration of a power storage system 1 including a power storage power conditioner according to an embodiment of the present invention. The power storage system 1 includes a power generation device 2, a transformer device 3, a power storage power conditioner 4, and a storage battery unit 5.

[0029] The power generation device 2 is a device capable of generating power, and is, for example, a photovoltaic (PV) unit, a fuel cell (FC) unit, a wind power generation unit, or the like. The power generation device 2 inputs the generated DC power to the transformer device 3. The transformer device 3 has an input unit 31, a transformer unit 32, an output unit 33, a control unit 34, and a communication unit 35. The DC power output from the power generation device 2 is input to the input unit 31. The transformer unit 32 transforms the DC power input to the input unit 31 to a first predetermined voltage. The transformer unit 32 is, for example, a non-insulated DC / DC converter or an insulated DC / DC converter. The output unit 33 inputs the DC power transformed to the first predetermined voltage to the storage power conditioner 4. The control unit 34 controls the transformer unit 32. The control unit 34 also has a processor such as a CPU or an MPU, and memories such as a RAM or a ROM. The control unit 34 may be configured with one CPU or MPU, or may be configured by combining multiple CPUs or multiple MPUs. The CPU or MPU is not limited to a single processor, and may be a multi-processor configuration. The control unit 34 executes various processes according to a program executablely deployed in the memory. The communication unit 35 communicates with the storage power conditioner 4 via a wired or wireless connection. The storage system 1 may include multiple power generation devices 2. The transforming device 3 may have multiple input units 31 connected to each of the multiple power generation devices 2, multiple transforming units 32, and multiple output units 33.

[0030] The storage power conditioner 4 has an input unit 41, a transformer unit 42, an input / output unit 43, a conversion unit 44, an input / output unit 45, a control unit 46, and a communication unit 47. DC power of a first predetermined voltage output from the output unit 33 of the transformer device 3 is input to the input unit 41. The transformer unit 42 transforms the first predetermined voltage of the DC power input to the input unit 41 to a second predetermined voltage. The transformer unit 42 is, for example, a non-insulated DC / DC converter or an insulated DC / DC converter. The input / output unit 43 inputs the DC power transformed to the second predetermined voltage to the storage battery unit 5. In addition, the DC power output from the storage battery unit 5 is input to the input / output unit 43. Input / Output The input unit 43 is an example of a first input / output unit. The transformer unit 42 transforms the voltage of the DC power input to the input / output unit 43 into a first predetermined voltage and outputs the DC power. The converter 44 is, for example, a DC / AC inverter. The converter 44 converts the DC power output from the input unit 41 or the transformer unit 42 into AC power. The input / output unit 45 outputs the AC power to the power system 6 or the load 7. The input / output unit 45 is an example of a second input / output unit. In addition, the AC power output from the power system 6 is input to the input / output unit 45. The converter 44 converts the AC power input to the input / output unit 45 into DC power and outputs the DC power. The transformer unit 42 transforms the voltage of the DC power output from the converter 44 into a second predetermined voltage. The controller 46 controls the transformer unit 42 and the converter 44. The controller 46 has a processor such as a CPU or an MPU and a memory such as a RAM or a ROM. The control unit 46 may be configured with one CPU or MPU, or may be configured by combining multiple CPUs or multiple MPUs. The CPU or MPU is not limited to a single processor, and may be a multi-processor configuration. The control unit 46 executes various processes according to a program executablely deployed in the memory. The communication unit 47 communicates with the storage battery unit 5 and the transforming device 3 via wired or wireless communication. Information received from the storage battery unit 5 and the transforming device 3 is transmitted to the control unit 46.

[0031] The storage battery unit 5 is a chargeable and dischargeable secondary battery, and for example, a lithium ion battery or various other types of secondary batteries can be applied. The first predetermined voltage and the third predetermined voltage are voltages suitable for outputting AC power to the power system 6 or the load 7. The second predetermined voltage is a voltage suitable for inputting DC power to the storage battery unit 5. The first predetermined voltage and the second predetermined voltage are different values. The first predetermined voltage and the third predetermined voltage may be the same value or different values.

[0032] FIG. 2 is a diagram showing the overall configuration of the energy storage system 1 according to the present embodiment. The energy storage system 1 includes a power generation device 2, a transformer device 3, a storage power conditioner 4, a storage battery unit 5, an operation unit 8, a display unit 9, a communication unit 10, a specific load distribution board 11, and a specific load 71. The power generation device 2 and the transformer device 3 are connected to each other by a cable or the like. The transformer device 3 and the storage power conditioner 4 are connected to each other by a cable or the like. The transformer device 3 is detachable from the storage power conditioner 4. Even if the transformer device 3 is not attached to the storage power conditioner 4, the storage power conditioner 4 can operate independently. In the example of FIG. 2, the number of the transformer devices 3 is one, but this is not limited thereto, and the number of the transformer devices 3 may be multiple, and the number of the transformer devices 3 can be increased or decreased.

[0033] A specific load distribution board 11 is connected to the storage power conditioner 4, and when the supply of AC power from the power grid 6 is stopped due to a power outage or the like, the inverter can switch to independent operation to supply power from at least one of the power generation device 2 and the storage battery unit 5 to a specific load 71 connected to the specific load distribution board 11.

[0034] The operation unit 8 is a remote controller that inputs an instruction signal to the storage power conditioner 4 and operates the storage power conditioner 4. The operation unit 8 may be configured with input devices such as a keyboard, a mouse, or a keyboard and operation buttons. The operation unit 8 may have a Home Energy Management System (HEMS) controller or a Virtual Power Plant (VPP) controller. The HEMS is a system that manages the power consumption of a home. The VPP is a system that collectively manages multiple small-scale power generation facilities through a network. The display unit 9 displays various information. The display unit 9 is, for example, a Cathode Ray Tube (CRT) display, a liquid crystal display, a plasma display, an organic EL (Electro Luminescence) display, or the like. The communication unit 10 is an interface that communicates with a server 15 connected to a network 14. The communication unit 10 includes, for example, a router and a modem. The network 14 includes, for example, a public network such as the Internet and a Local Area Network (LAN). It is not necessary to include all of the components of the storage system 1 shown in FIG. 2. Furthermore, in implementing the power storage system 1, components of the power storage system 1 may be added or deleted as appropriate.

[0035] <Recognition process of the rated capacity of the storage battery unit> Hereinafter, a process in which the control unit 46 recognizes the rated capacity, which is a characteristic of the storage battery unit 5, will be described with reference to FIG.

[0036] Here, it is assumed that storage battery units with three types of rated capacities, 6.5 kWh, 9.8 kWh, and 16.4 kWh, are preset as candidates for the storage battery units 5 connectable to the storage power conditioner 4. The candidates for the storage battery units 5 connectable to the storage power conditioner 4 are not limited to those having these rated capacities, and can be set as appropriate. The rated capacities of the storage battery units 5 connectable to such storage power conditioner 4 are set by the operation unit 8 or by an external device via a network as part of the system configuration, and are stored in a predetermined area of ​​the memory included in the control unit 46.

[0037] In this embodiment, the control unit 46 recognizes the rated capacity of the storage battery unit 5 by transmitting an Initialize command to the storage battery unit 5 via the communication unit 47. The Initialize command includes identification information called a Fixed Number that is assigned to each type of storage battery unit 5. For example, the Fixed Numbers 0, 1, and 2 correspond to the 6.5 kWh, 9.8 kWh, and 16.4 kWh storage battery units 5, respectively. When the storage battery unit 5 receives its own Fixed Number from the storage power conditioner 4 by the Initialize command, it returns a normal response as a response, and when it receives a Fixed Number different from its own Fixed Number, it returns an abnormal response as a response or does not return a response.

[0038] First, the control unit 46 transmits an Initialize command including a fixed number of 6.5 kWh to the storage battery unit 5 via the communication unit 47 (step S1). In response to this, the control unit 46 determines whether the response received by the communication unit 47 from the storage battery unit 5 is a normal response, an abnormal response, or no response (step S2).

[0039] If the communication unit 47 receives a normal response, the control unit 46 determines that the rated capacity of the connected storage battery unit 5 is 6.5 kWh, and stores this in a specified area of ​​the memory (EEPROM) as information about the storage battery unit 5 connected to the storage power conditioner 4 (step S3). When the communication unit 47 receives the abnormal response, the control unit 46 transmits an Initialize command including a fixed number of 9.8 kWh to the storage battery unit 5 via the communication unit 47 (step S4). If the communication unit 47 does not receive a response from the storage battery unit 5, it determines whether or not a predetermined time has elapsed (step S5), and if the predetermined time has not elapsed, the process returns to step S2. If the predetermined time has elapsed without receiving a response from the storage battery unit 5, the process proceeds to step S4.

[0040] Following step S4, the control unit 46 determines whether the response received by the communication unit 47 from the storage battery unit 5 is a normal response, an abnormal response, or no response (step S6).

[0041] When the communication unit 47 receives a normal response, the control unit 46 determines that the rated capacity of the connected storage battery unit 5 is 9.8 kWh, and stores this in a predetermined area of ​​the memory as information on the storage battery unit 5 connected to the storage power conditioner 4 (step (P7). When the communication unit 47 receives the abnormal response, the control unit 46 transmits an Initialize command including a fixed number of 16.4 kWh to the storage battery unit 5 via the communication unit 47 (step S8). If the communication unit 47 does not receive a response from the storage battery unit 5, it determines whether or not a predetermined time has elapsed (step S9), and if the predetermined time has not elapsed, the process returns to step S6. If the predetermined time has elapsed without receiving a response from the storage battery unit 5, the process proceeds to step S8.

[0042] Following step S8, the control unit 46 determines whether the response received by the communication unit 47 from the storage battery unit 5 is a normal response, an abnormal response, or no response (step S10).

[0043] If the communication unit 47 receives a normal response, the control unit 46 determines that the rated capacity of the connected storage battery unit 5 is 16.4 kWh, and stores this in a specified area of ​​the memory as information about the storage battery unit 5 connected to the storage power conditioner 4 (step S11). If the communication unit 47 receives an abnormality response, the control unit 46 determines that there is an abnormality in the storage battery connection (step S12), and ends the process. If the communication unit 47 does not receive a response from the storage battery unit 5, it determines whether or not a predetermined time has elapsed (step S13), and if the predetermined time has not elapsed, the process returns to step S10. If the predetermined time has elapsed without receiving a response from the storage battery unit 5, the process proceeds to step S12.

[0044] The order in which the Initialize command containing a Fixed Number is sent first is not limited to the above-mentioned order, but since the rated capacity of the connected storage battery unit 5 is stored in memory, when the storage power conditioner 4 is reset or the power is turned off, the Initialize command containing the Fixed Number corresponding to the rated capacity stored in memory may be sent first.

[0045] Through the above-described processing, the storage power conditioner 4 can recognize the rated capacity of the connected storage battery unit 5. By controlling the output of the transformer 42 according to the rated capacity recognized in this manner, appropriate charge and discharge control can be performed without damaging the storage battery unit 5. In other words, storage battery units 5 having multiple types of rated capacities can be connected to the storage power conditioner 4, enabling operation according to different rated capacities, and improving the degree of freedom in the configuration of the storage system 1 including the storage power conditioner 4 and the storage battery unit 5.

[0046] <Charge / discharge control during stand-alone operation> Hereinafter, the charge / discharge control of the power storage system 1 during the independent operation will be described with reference to Fig. 4. Fig. 4 is a flowchart showing the procedure of the charge / discharge control of the power storage system 1 during the independent operation.

[0047] The energy storage system 1 is connected to a power grid 6 to operate the storage battery unit 5 and the power generation device 2, but in the event of a power outage or other interruption in the power supply from the power grid 6, the energy storage system 1 is disconnected from the power grid 6 and operates independently of the power grid 6. During the independent operation, the DC power input from the power generation device 2 to the input unit 41 and / or the DC power output from the storage battery unit 5 and transformed by the transformer unit 42 is converted to AC power by the converter unit 44, output from the input / output unit 45, and supplied to the specific load 71 connected to the specific load distribution board 11. At this time, the input / output unit 45 outputs single-phase two-wire 100V AC power. The force is output. During the independent operation, the load 7 may be connected to the storage power conditioner 4 via a transformer unit and a full-load switching distribution board. Here, the load 7 is also called a general load in contrast to a specific load, is connected to a main distribution board, and is a load to which AC power is supplied from the power system 6 during grid-connected operation. The full-load switching distribution board and the load 7 can be connected in various ways. AC power can be supplied to the load 7 connected to an outlet for independent output provided in the storage power conditioner 4. In addition, the input / output unit 45 is connected to a specific load distribution board via the main distribution board or directly, and can supply AC power to a load (specific load) 71 connected to the specific load distribution board. At this time, single-phase two-wire 100V AC power is output from the input / output unit 45.

[0048] First, the control unit 46 acquires the output power value P1 of the transforming device 3 (step S21). As described above, the control unit 34 of the transforming device 3 has an output power measurement unit 341 that measures the power value P1 of the DC power output to the input unit 41 from the current value of the DC power output from the output unit 33 and the output voltage value of the transforming unit 32, both measured by the CT 3411. The power value P1 measured by the output power measurement unit 341 is transmitted from the control unit 34 to the control unit 46 of the storage power conditioner 4 by communication between the communication unit 35 and the communication unit 47. The control unit 46 is an example of a first power value acquisition unit of the present invention.

[0049] Next, the control unit 46 acquires, from the input / output unit 45, an output current value P2 of the AC power output to the load (load or specific load) 7 (step S22). The input / output unit 45 is provided with an output power measurement unit 451 that measures the power value of the AC power output from the conversion unit 44 and output to the outside of the power storage power conditioner 4 via the input / output unit 45. The control unit 46 acquires the output power value P2 from the output power measurement unit 451. The control unit 46 may calculate the power value after acquiring the current value and voltage value measured by the CT and voltmeter provided in the input / output unit 45.

[0050] The control unit 46 compares the power value P1 with the power value P2 to determine whether or not P1>P2 (step S23). If it is determined in step S23 that the answer is Yes, i.e., that P1>P2, the DC power input to the input unit 41 is supplied to the load 7 and also charges the storage battery unit 5 (step S24). That is, a part of the DC power input to the input unit 41 is transformed by the transformer unit 42, and the DC power output from the transformer unit 42 is output to the storage battery unit 5 via the input / output unit 43. Then, the control unit 46 determines whether or not the remaining battery charge of the storage battery unit 5 is equal to or greater than a predetermined upper limit value according to the rated capacity (step S25). In step S25, if it is determined that the remaining battery level is less than the upper limit, the process returns to step S24, and if it is determined that the remaining battery level is equal to or greater than the upper limit, the process proceeds to step S26. Here, if it is determined in step S25 that the remaining battery level is less than the upper limit, the process returns to step S24, but it may also return to step S21.

[0051] If it is determined in step S23 that the answer is No, that is, that P1≦P2, the storage battery unit 5 is discharged (step S27). The DC power discharged from the storage battery unit 5 is input from the input / output unit 43 and transformed by the transformer unit 42. The DC power output from the transformer unit 42 and the DC power input from the input unit 41 are converted to AC power by the converter 44 and supplied to the load 7 via the input / output unit 45. Then, the control unit 46 determines whether or not the remaining battery charge of the storage battery unit 5 is equal to or lower than a predetermined lower limit value according to the rated capacity (step S28). In step S28, if it is determined that the remaining battery level is greater than the lower limit, the process returns to step S27, and if it is determined that the remaining battery level is equal to or less than the lower limit, the process proceeds to step S26. If it is determined in step S28 that the remaining battery charge is greater than the lower limit, the process returns to step S27, but it may also be arranged to return to step S21.

[0052] In step S26, the control unit 46 determines whether or not to end the independent operation of the power storage system 1. When the independent operation is to be ended due to reasons such as the resumption of power supply from the power grid 6, the charge / discharge control of the storage battery unit 5 is ended. If the independent operation is to be continued, the process returns to step 21.

[0053] By controlling the charging and discharging of the storage battery unit 5 in this manner, the power generated by the power generation device 2 during independent operation is given priority for supply to the load 7 or the specific load 71, and the storage battery unit 5 is charged when there is surplus power. Then, when the power generated by the power generation device 2 alone is insufficient to supply to the load 7 or the specific load 71, the storage battery unit 5 is discharged to increase the power supplied to the load 7 or the specific load 71. In this way, the load 7 or the specific load 71 can be operated more stably even during independent operation.

[0054] When performing the charge / discharge control of the storage battery unit 5 described above, if the power generation device 2 is a PV unit, the control unit 34 of the transformer device 3 performs MPPT (Maximum Power Point Tracking) control and operates the PV unit so as to follow the maximum power of the PV unit. When charging the storage battery unit 5, the charging power can be automatically set by a process described later. The charging power of the storage battery unit 5 may be set in advance according to the rated capacity, or may be set by the user via the operation unit 8. Also, the server 15 may set the charging power of the storage battery unit 5 via the network 14.

[0055] In the following, the components of the present invention will be described with reference to the reference numerals in the drawings in order to make it possible to compare the components of the present invention with the configurations of the embodiments. <Invention 1> an input unit (41) for receiving DC power; a first transformer unit (42) that transforms the voltage of the DC power; a first input / output unit (43) that outputs the DC power transformed by the first transformer unit (42) to the storage battery unit (5) and receives the DC power from the storage battery unit (5); A converter (44) for converting DC power into AC power; a second input / output unit (45) that outputs the AC power converted by the conversion unit (44) to an electric power system (6) or a load (7) and receives AC power from the electric power system (6); a first control unit (46) that controls the first transformer unit (42) and the converter unit (44); a first communication unit (47) for communicating with the storage battery unit (5); Equipped with The first transformer unit (42) receives the DC power input to the input unit (41) and the DC power input to the second input / output unit (45) and converted by the conversion unit (44), The converter (44) receives the DC power output from the first transformer (42) and the DC power input to the input unit (41), The storage power conditioner (4) is characterized in that the first control unit (46) transmits a command, in which a response corresponding to the characteristics of the storage battery unit is defined, to the storage battery unit (5) via the first communication unit (47), and controls an output of the first transformer unit (42) or the conversion unit (44) in accordance with the response of the storage battery unit (5) to the command. [Explanation of symbols]

[0056] 4: Energy storage power conditioner 5: Battery unit 6: Power system 7: Load 41: Input section 43: Transformer section 43: Input / output section 44: Conversion section 45: Input / output section 46: Control section 47: Communications Department

Claims

1. A storage power conditioner that can connect any one of storage battery units having different characteristics, an input unit to which DC power is input; a first transforming unit that transforms a voltage of DC power and outputs the transformed DC power; a first input / output unit that outputs the DC power transformed by the first transformer unit to the storage battery unit and receives the DC power from the storage battery unit; A conversion unit that converts DC power into AC power and converts AC power into DC power; a second input / output unit that outputs the AC power converted by the conversion unit to a power system or a load and receives AC power from the power system; A first control unit that controls the first transformer unit and the converter unit; A first communication unit that communicates with the storage battery unit; Equipped with The first transformer receives the DC power input to the input unit and the DC power obtained by converting the AC power input to the second input / output unit by the converter, The DC power output from the first transformer unit and the DC power input to the input unit are input to the converter unit, The first control unit transmits a command assigned to each of the characteristics of the storage battery units connectable to the storage power conditioner via the first communication unit in order to identify the characteristics of the connected storage battery unit, receives a response to the command from the storage battery unit, and controls the output of the first transformer unit in accordance with the received result.

2. The storage power conditioner according to claim 1, characterized in that the first control unit determines that a connection abnormality has occurred in the storage battery unit when an abnormal response is received from the connected storage battery unit in response to the command via the first communication unit, or when no response is received within a predetermined time period in response to the command.

3. 3. The storage power conditioner according to claim 1, wherein the characteristic of the storage battery unit is a rated capacity of the storage battery unit.

4. a first power value acquisition unit that acquires a DC power value input to the input unit, and a second power value acquisition unit that acquires an AC power value output from the second input / output unit to the load, 4. The storage power conditioner according to claim 3, wherein the first control unit controls the first transformer unit in accordance with the rated capacity of the storage battery unit, based on a DC power value input to the input unit and an AC power value output from the second input / output unit to the load.

5. When a DC power value input to the input unit is P1 and an AC power value output from the second input / output unit to the load is P2, The first control unit is When P1>P2, the storage battery unit is charged by the DC power input to the input unit in accordance with the rated capacity; 5. The storage power conditioner according to claim 4, characterized in that, when P1 < P2, the DC power discharged from the storage battery unit is input to the conversion unit together with the DC power input to the input unit, and the converted AC power is output to the load from the second input / output unit.

6. A storage system capable of using any of storage battery units having different characteristics, a first transforming unit that transforms a voltage of DC power and outputs the transformed DC power; a second transforming unit that transforms the DC power input from the power generation device; a first input / output unit that outputs the DC power transformed by the first transformer unit to the storage battery unit and receives the DC power from the storage battery unit; A conversion unit that converts DC power into AC power and converts AC power into DC power; a second input / output unit that outputs the AC power converted by the conversion unit to a power system or a load and receives AC power from the power system; A first control unit that controls the first transformer unit and the converter unit; A first communication unit that communicates with the storage battery unit; Equipped with The first transformer receives DC power input from the power grid and converted by the converter, and DC power input from the power generation device and transformed by the second transformer, The converter receives DC power input from the storage battery unit and transformed by the first transformer, and DC power input from the power generation device and transformed by the second transformer, The first control unit transmits a command assigned to each of the characteristics of the usable storage battery unit via the first communication unit in order to identify the characteristics of the connected storage battery unit, receives a response to the command from the storage battery unit, and controls the output of the first transformer unit to the storage battery unit in accordance with the received result.

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