Output control device and battery storage system

Abstract

The present invention provides an output control device and battery storage system that can easily secure the necessary charging and discharging power even when some of multiple power converters malfunction. [Solution] The output control device includes an information acquisition unit that acquires status monitoring information of multiple power converters that control the charging and discharging operations of multiple storage batteries, and a control unit that, based on the status monitoring information, causes each of the multiple power converters to output power of an amount corresponding to multiple charge / discharge command values. The control unit performs overload control when, while a set rated power is set for the multiple power converters, some of the multiple power converters stop abnormally and the required charge / discharge power is greater than the sum of the set rated powers of the remaining power converters, by setting charge / discharge command values ​​equal to or greater than the set rated power for at least some of the remaining power converters.

Description

Technical Field

[0001] Embodiments of the present invention relate to an output control device and a battery system.

Background Art

[0002] There is a battery system including a plurality of batteries, a plurality of power conversion devices, and an output control device. The plurality of power conversion devices are provided corresponding to each of the plurality of batteries. The plurality of power conversion devices are connected to each of the plurality of batteries, and perform charging of the plurality of batteries based on power supplied from the outside and discharging of the power stored in the plurality of batteries to the outside. The output control device controls the charging and discharging operations of the plurality of batteries by the plurality of power conversion devices.

[0003] The battery system is used, for example, in a distributed power source system using distributed power sources. The distributed power source system includes a plurality of distributed power sources and a plurality of power conversion devices. The distributed power sources are, for example, generators using renewable energy such as solar power generators, wind power generators, and geothermal power generators. The plurality of power conversion devices are connected to each of the plurality of distributed power sources and also connected to the power grid, convert the power generated by the plurality of distributed power sources into power corresponding to the power grid, and supply the converted power to the power grid or a load (consumer) connected to the power grid. Thereby, in the distributed power source system, power can be sold to the power grid or power purchase from the power grid can be suppressed.

[0004] On the other hand, in distributed power systems, the output can change rapidly in a short period of time due to factors such as weather fluctuations (fluctuations in solar radiation if the distributed power source is a solar power generator), potentially deviating from the rate of change defined by the Transmission System Operator (TSO). When the output of a distributed power system deviates from the rate of change, the frequency of the power grid can become disrupted, potentially making it difficult to transmit power stably. For this reason, if the output of a distributed power system frequently deviates from the rate of change, the Transmission System Operator may request improvements from the operators of the distributed power system.

[0005] By introducing a battery storage system into a distributed power system, fluctuations in the output of the distributed power system can be suppressed. For example, when the output of the distributed power system increases rapidly, multiple batteries are charged, and the surplus power that deviates from the rate of change is stored in multiple batteries. Also, for example, when the output of the distributed power system decreases rapidly, multiple batteries are discharged, and the deficiency power that deviates from the rate of change is discharged from multiple batteries. This prevents the output of the distributed power system from deviating from the rate of change.

[0006] In the battery storage system described above, some of the power converters may malfunction or fail to shut down. If some of the power converters malfunction, it may become impossible to secure the necessary charging and discharging power (the total power of the charging and discharging power of the multiple batteries). For example, when a distributed power system is introduced into the battery storage system, there is a concern that the necessary charging and discharging power may be insufficient, increasing the likelihood that the output of the distributed power system will deviate from the rate of change.

[0007] Therefore, it is desirable that battery storage systems and the output control devices used therein be designed to easily secure the necessary charging and discharging power even when some of the multiple power converters malfunction. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2020-129949 [Overview of the project] [Problems that the invention aims to solve]

[0009] Embodiments of the present invention provide an output control device and a battery storage system that can easily secure the necessary charging and discharging power even when some of multiple power conversion devices malfunction. [Means for solving the problem]

[0010] According to an embodiment of the present invention, an output control device for controlling the charging and discharging operations of multiple storage batteries by multiple power converters comprises: an information acquisition unit that acquires status monitoring information including information on the magnitude of the charge and discharge power of the multiple power converters, information on the remaining capacity of the multiple storage batteries, and information on abnormalities in the multiple power converters; and a control unit that calculates a plurality of charge and discharge command values ​​representing the magnitude of the power to be output from each of the multiple power converters based on the status monitoring information, and transmits each of the calculated plurality of charge and discharge command values ​​to each of the multiple power converters corresponding to the plurality of power converters, thereby causing each of the multiple power converters to output power of a magnitude corresponding to the plurality of charge and discharge command values. The present invention provides an output control device that sets a set rated power lower than the equipment rated power, which represents the amount of power that the device can output, for the plurality of power converters, detects abnormal shutdowns of the plurality of power converters based on the abnormality information included in the status monitoring information, and performs overload control by setting a charge / discharge command value equal to or greater than the set rated power for at least a portion of the remaining power converters when the set rated power has been set for the plurality of power converters, and the amount of required charge / discharge power is greater than the sum of the set rated powers of the remaining power converters. [Effects of the Invention]

[0011] An output control device and battery system are provided that make it easier to secure the necessary charging and discharging power even when some of the multiple power converters malfunction. [Brief explanation of the drawing]

[0012] [Figure 1] This is a block diagram schematically representing a solar power generation system according to the embodiment. [Figure 2] This is a flowchart schematically illustrating an example of the operation of a solar power generation system according to the embodiment. [Figure 3] This is a flowchart schematically illustrating an example of the operation of a solar power generation system according to the embodiment. [Modes for carrying out the invention]

[0013] Each embodiment will be described below with reference to the drawings. Please note that the drawings are schematic or conceptual, and the relationships between the thickness and width of each part, as well as the ratios of the sizes of the parts, are not necessarily identical to those of reality. Furthermore, even when representing the same part, the dimensions and ratios may differ between drawings. In this specification and in each figure, elements similar to those described above are denoted by the same reference numerals, and detailed explanations are omitted as appropriate.

[0014] Figure 1 is a block diagram schematically representing a photovoltaic power generation system according to an embodiment. As shown in Figure 1, the solar power generation system 10 includes an output control device 12 and multiple power converters 14 and 16. The multiple power converters 14 are connected to multiple solar panels 2 (distributed power sources) and also to the power grid PS. The multiple power converters 16 are connected to multiple storage batteries 4 and also to the power grid PS. The power of the power grid PS is AC power. In other words, the power grid PS is an AC power grid. The solar power generation system 10 is an example of a distributed power source system that incorporates a storage battery system.

[0015] The solar power generation system 10 further includes, for example, multiple transformers 18, 20, 22 and power receiving and transforming equipment 24. Multiple power converters 14 are connected to the power grid PS via each of the transformers 18, 22 and power receiving and transforming equipment 24. Multiple power converters 16 are connected to the power grid PS via each of the transformers 20, 22 and power receiving and transforming equipment 24.

[0016] The power receiving and transforming equipment 24 includes, for example, transformers and circuit breakers. However, the transformers 18, 20, 22 and the power receiving and transforming equipment 24 are provided as needed and can be omitted. The configuration of the connection between the multiple power converters 14 and the power system PS can be any configuration that allows the multiple power converters 14 to be appropriately connected to the power system PS. Similarly, the configuration of the connection between the multiple power converters 16 and the power system PS can be any configuration that allows the multiple power converters 16 to be appropriately connected to the power system PS.

[0017] Multiple power converters 14 convert the power supplied from multiple solar panels 2 into power compatible with the power grid PS, and output the converted power to the power grid PS. The power supplied from multiple solar panels 2 is DC power. That is, multiple power converters 14 convert the DC power supplied from multiple solar panels 2 into AC power compatible with the power grid PS, and output the converted AC power to the power grid PS.

[0018] The solar power generation system 10 is used, for example, in a power generation facility equipped with a plurality of solar panels 2. The plurality of power conversion devices 14 perform, for example, power sales of the power generated by each solar panel 2 to the power grid PS. The plurality of power conversion devices 14 may supply, for example, the power generated by each solar panel 2 to a load (consumer) connected to the power grid PS. The solar power generation system 10 may be, for example, a self-consumption type system.

[0019] The number of the plurality of power conversion devices 14 is, for example, the same as the number of the plurality of solar panels 2. The plurality of power conversion devices 14 are connected to, for example, each of the plurality of solar panels 2. However, the number of the plurality of power conversion devices 14 does not necessarily have to be the same as the number of the plurality of solar panels 2. For example, a plurality of solar panels 2 may be connected to one power conversion device 14. Conversely, a plurality of power conversion devices 14 may be connected to one solar panel 2. The configuration of the plurality of power conversion devices 14 may be any configuration capable of appropriately outputting the power supplied from the plurality of solar panels 2 to the power grid PS.

[0020] The plurality of power conversion devices 14 have, for example, a converter 30 and a communicator 32. The converter 30 is connected to the solar panel 2 and the power grid PS. The converter 30 converts the power supplied from the connected solar panel 2 into power corresponding to the power grid PS, and outputs the converted power to the power grid PS side (the power grid PS or the load).

[0021] The communicator 32 communicates with the output control device 12. The converter 30 performs, for example, conversion of the power supplied from the solar panel 2 based on a signal input from the output control device 12 via the communicator 32.

[0022] A plurality of power conversion devices 16 charge and discharge a plurality of storage batteries 4. In other words, the plurality of power conversion devices 16 perform a charging operation of charging the connected storage battery 4 and a discharging operation of discharging the connected storage battery 4. In the charging operation, for example, the plurality of power conversion devices 16 convert the power (AC power) output from the plurality of power conversion devices 14 to the power system PS side into power (DC power) corresponding to the storage battery 4, and supply the converted power to the connected storage battery 4, thereby charging the connected storage battery 4. In the discharging operation, for example, the plurality of power conversion devices 16 convert the power (DC power) stored in the connected storage battery 4 into power (AC power) corresponding to the power system PS, and output the converted power to the power system PS side, thereby discharging the connected storage battery 4.

[0023] In the photovoltaic power generation system 10, for example, when the generated power of the plurality of solar panels 2 suddenly increases, the plurality of storage batteries 4 are charged, and when the generated power of the plurality of solar panels 2 suddenly decreases, the plurality of storage batteries 4 are discharged. Thereby, in the photovoltaic power generation system 10, for example, a sudden change in the power output to the power system PS side can be suppressed, or an appropriate amount of power required by the load can be supplied to the load.

[0024] Also, for example, when the rate of change of the power supplied to the power system PS is predetermined between the administrator of the photovoltaic power generation system 10 and the general power transmission and distribution business operator who manages and operates the power system PS, it is possible to suppress the power output from the photovoltaic power generation system 10 to the power system PS from deviating from the rate of change.

[0025] In the solar power generation system 10, for example, if the amount of power generated by multiple solar panels 2 is greater than the amount of power that can be output to the power grid PS, the excess power generated by the multiple solar panels 2 can be stored in multiple storage batteries 4, thereby preventing the waste of excess power. For example, excess power generated during the day can be stored in multiple storage batteries 4, and during times when power generation decreases, such as from evening to night, the power stored in the multiple storage batteries 4 can be output to the power grid PS. This helps to prevent the waste of excess power.

[0026] The number of power converters 16 is, for example, the same as the number of batteries 4. The power converters 16 are connected to each of the batteries 4, for example. However, similar to the power converters 14, the number of power converters 16 does not necessarily have to be the same as the number of batteries 4. The configuration of the power converters 16 can be any configuration that can properly perform the charging and discharging operations of the batteries 4.

[0027] The multiple power converters 16 include, for example, a converter 34 and a communication device 36. The converter 34 is connected to the storage battery 4 and the power grid PS. The converter 34 performs charging and discharging operations on the connected storage battery 4.

[0028] The communication device 36 communicates with the output control device 12. The converter 34 performs charging and discharging operations of the connected storage battery 4 based on signals input from the output control device 12 via the communication device 36.

[0029] The solar power generation system 10 is further equipped with, for example, a power meter 26. The power meter 26 measures the magnitude of the power output from the multiple power converters 14, 16 to the power system PS at the interconnection point CP between the multiple power converters 14, 16 and the power system PS. For example, if each power converter 14, 16 is connected to the power system PS via each transformer 18, 20, 22, substation equipment 24, etc., the power meter 26 is installed closer to the interconnection point CP than each transformer 18, 20, 22, substation equipment 24. The power meter 26 is installed, for example, in the vicinity of the interconnection point CP. In this way, the power meter 26 measures the magnitude of the power output from each power converter 14, 16 to the interconnection point CP (power system PS side).

[0030] The output control device 12 controls the output of multiple power converters 14 and multiple power converters 16. In other words, the output control device 12 controls the charging and discharging operations of multiple storage batteries 4 by multiple power converters 16.

[0031] The output control device 12 comprises an information acquisition unit 40 and a control unit 42. The information acquisition unit 40 acquires, for example, information on output control values ​​representing the magnitude of power output from multiple power converters 14 and 16 to the power system PS, information on measured values ​​obtained by measuring the magnitude of power output from multiple power converters 14 and 16 to the power system PS at the interconnection point CP between the multiple power converters 14 and 16 and the power system PS, and status monitoring information for each of the multiple power converters 14 and 16.

[0032] In other words, the output control value information represents the upper limit of the amount of power that can be output from multiple power converters 14 and 16 to the power grid PS side. The output control value is set, for example, by a general transmission and distribution company that manages the power grid PS in order to adjust the supply and demand balance of the power grid PS.

[0033] The information acquisition unit 40 acquires output control value information from a power server managed by a general power transmission and distribution company, for example, by communicating with the power server. However, the method of acquiring output control value information is not limited to the above, and any method that can appropriately acquire output control value information is acceptable. Output control value information may also be acquired from another control device that controls the operation of multiple power converters 14, 16, for example. Output control value information may also be acquired from an operation unit such as a keyboard or mouse provided on the output control device 12, for example. In other words, output control value information may be manually input to the information acquisition unit 40 via the operation unit.

[0034] The information acquisition unit 40 acquires measurement information from the power meter 26 by communicating with the power meter 26, for example. However, the method for acquiring measurement information is not limited to the above, and any method that can appropriately acquire measurement information is acceptable.

[0035] The information acquisition unit 40 acquires status monitoring information from each of the multiple power converters 14 and 16 by communicating with each of the communication devices 32 of the multiple power converters 14 and each of the communication devices 36 of the multiple power converters 16, for example. However, the method of acquiring status monitoring information is not limited to the above, and any method that can appropriately acquire status monitoring information is acceptable. Status monitoring information may also be acquired from another control device that controls the operation of the multiple power converters 14 and 16, for example.

[0036] The status monitoring information obtained from the power converter 14 includes, for example, information on the magnitude of the power generated and output from the power converter 14 to the power system PS side, and information on abnormalities in the power converter 14. The information on abnormalities in the power converter 14 includes, for example, information indicating whether or not the power converter 14 has stopped due to a malfunction or other reason.

[0037] The status monitoring information acquired from the power converter 16 includes, for example, information on the magnitude of the charging and discharging power of the power converter 16, information on the remaining capacity (charge rate) of the connected storage battery 4, and information on abnormalities in the power converter 16. The information on abnormalities in the power converter 16 includes, for example, information indicating whether or not the power converter 16 has stopped due to a malfunction or other reason. In other words, the information acquisition unit 40 acquires status monitoring information that includes information on the magnitude of the charging and discharging power of multiple power converters 16, information on the remaining capacity of multiple storage batteries 4, and information on abnormalities in multiple power converters 16.

[0038] The power converter 16 calculates the remaining capacity of the battery 4, for example by measuring the voltage value of the battery 4, and transmits the calculated remaining capacity of the battery 4 to the output control device 12. The power converter 16 may also obtain the remaining capacity of the battery 4 from a battery management system provided in conjunction with the battery 4, for example, and transmit the obtained remaining capacity of the battery 4 to the output control device 12. The information acquisition unit 40 may also directly obtain information on the remaining capacity of the battery 4 from a battery management system, for example.

[0039] The information acquisition unit 40 is a communication device for communicating with, for example, a power server, a power meter 26, and each communication device 32, 36. The information acquisition unit 40 may also have a function for receiving operation signals from the operation unit. The configuration of the information acquisition unit 40 can be any configuration that can appropriately acquire information on output control values, measured values, and status monitoring information of each power converter 14, 16.

[0040] The control unit 42 controls the output of multiple power converters 14 and 16 based on, for example, information on the output control value, information on the measured value, and status monitoring information for each power converter 14 and 16. The control unit 42 calculates multiple power generation command values ​​that represent the magnitude of power output from each of the multiple power converters 14 based on the information on the output control value, information on the measured value, and status monitoring information for each power converter 14, and also calculates multiple charge / discharge command values ​​that represent the magnitude of power output from each of the multiple power converters 16 based on the information on the output control value, information on the measured value, and status monitoring information for each power converter 16. The control unit 42 calculates multiple power generation command values ​​corresponding to each of the multiple power converters 14 and multiple charge / discharge command values ​​corresponding to each of the multiple power converters 16 so that the total magnitude of power output from each of the multiple power converters 14 and 16 to the power system PS side corresponds to the output control value.

[0041] The control unit 42 communicates with multiple power converters 14 (communicators 32), for example, and transmits each of the calculated multiple power generation command values ​​to each of the corresponding multiple power converters 14, thereby causing each of the multiple power converters 14 to output power of an magnitude corresponding to the multiple power generation command values. Then, the control unit 42 communicates with multiple power converters 16 (communicators 36), for example, and transmits each of the calculated multiple charge / discharge command values ​​to each of the corresponding multiple power converters 16, thereby causing each of the multiple power converters 16 to output power of an magnitude corresponding to the multiple charge / discharge command values. In this way, the control unit 42 controls the output of the multiple power converters 14 and 16 so that the total amount of power output from each of the multiple power converters 14 and 16 to the power system PS side is equal to the output control value.

[0042] Furthermore, the control unit 42 detects abnormal shutdowns of multiple power converters 16 based on information regarding abnormalities included in the status monitoring information.

[0043] In the solar power generation system 10, a set rated power lower than the equipment rated power, which represents the amount of power that each device can output, may be set for multiple power converters 16. The control unit 42 of the output control device 12 sets the set rated power for the multiple power converters 16.

[0044] The set rated power is set, for example, when limiting the output of the power converter 16. For example, if a power generation facility requires a power converter 16 with a rated power of 800kW, the manufacturer's product lineup may not include a power converter 16 with an 800kW rated power. In this case, a power converter 16 with a rated power of 1000kW is set to a rated power of 800kW, and the output is limited to 800kW, thereby allowing the 1000kW power converter 16 to be introduced into the power generation facility as a substitute for the 800kW power converter 16. In this case, the control unit 42 sets the rated power according to the output limit for multiple power converters 16.

[0045] Furthermore, the set rated power is also set when output control is performed by, for example, a general transmission and distribution operator or a power company. A general transmission and distribution operator or a power company may set the set rated power for each of the multiple power converters 16 and perform output control by, for example, transmitting an output control command value to the output control device 12 according to the supply and demand balance of the power grid PS. For example, a power converter 16 with a rated power of 1000kW may be set to a set rated power of 500kW, and the rated power of the power converter 16 may be controlled to 500kW. In this case, the control unit 42 sets the set rated power for the multiple power converters 16 according to the output control based on the received output control command value. The set rated power may also be set based on both the output limit and output control described above.

[0046] Furthermore, in the solar power generation system 10, some of the multiple power converters 16 may malfunction or otherwise fail to shut down. If some of the multiple power converters 16 malfunction, it may become impossible to secure the necessary charging and discharging power. For example, there is a concern that insufficient charging and discharging power may cause the output of the solar power generation system 10 to deviate from the rate of change, or that generated power may be wasted.

[0047] For example, if a set rated power is configured for multiple power converters 16, and some of the power converters 16 malfunction, it is conceivable that the remaining power converters 16 would continue to operate at their set rated power. However, in this case, even though the remaining batteries 4 and power converters 16 have sufficient capacity, the output is limited by the set rated power, which may increase the likelihood of insufficient charging and discharging power.

[0048] For example, suppose 10 power converters 16, each with a rated power of 1000kW, are operated with a set rated power of 500kW. If one power converter 16 malfunctions in this state, the remaining 9 power converters 16 operating at their set rated powers can supply 4500kW of charge and discharge power. On the other hand, the remaining 9 power converters 16 operating at their rated powers can supply 9000kW of charge and discharge power. Therefore, if a charge and discharge power in the range of 4500kW to 5000kW is required, corresponding to the maximum value before the malfunction, the required charge and discharge power will be insufficient, even though the remaining battery 4 and power converters 16 have sufficient capacity.

[0049] Therefore, when the control unit 42 has set a set rated power for multiple power converters 16, and some of the multiple power converters 16 malfunction, it performs overload control to set charge / discharge command values ​​equal to or greater than the set rated power for at least some of the remaining power converters 16, as necessary. In overload control, the control unit 42 sets charge / discharge command values ​​equal to or greater than the set rated power and equal to or less than the equipment rated power, as necessary. The remaining power converters 16 are, in other words, the normal power converters 16 that have not malfunctioned.

[0050] For example, suppose that in the above example, 5000kW of charging and discharging power is required. In this case, the control unit 42 would, for example, operate four of the remaining nine power converters 16 at the set rated power of 500kW. Then, the control unit 42 would, for example, perform overload control on five of the power converters 16, equally dividing and adding the charging and discharging power of the abnormally stopped power converter 16, so that the remaining five power converters 16 operate at 600kW, which is above the set rated power. This ensures that even if one power converter 16 abnormally stops, the remaining power converters 16 can secure the necessary charging and discharging power.

[0051] Thus, overload control does not need to be performed on all of the remaining power converters 16; it only needs to be performed on any number of the remaining power converters 16 that can supply the charging and discharging power to the abnormally stopped power converter 16. The number of power converters 16 to perform overload control can be appropriately determined according to the required charging and discharging power (the charging and discharging power of the abnormally stopped power converter 16), the remaining capacity of the battery 4 connected to the remaining power converters 16, etc. Similarly, the power converters 16 to perform overload control from the remaining multiple power converters 16 can be appropriately selected according to the required charging and discharging power, the remaining capacity of the battery 4, etc.

[0052] The amount of charge / discharge power to be allocated to the power converter 16 performing overload control (the amount of power to be equal to or greater than the set rated power) is calculated, for example, by dividing the charge / discharge power of the abnormally stopped power converter 16 by the number of power converters 16 performing overload control, as described above. In other words, the amount of charge / discharge power to be allocated to the power converter 16 performing overload control is calculated so as to distribute the charge / discharge power of the abnormally stopped power converter 16 equally among the power converters 16 performing overload control.

[0053] However, the method for calculating the magnitude of the charge / discharge power to be allocated to the power converter 16 performing overload control (the charge / discharge command value of the power converter 16 performing overload control) is not limited to the above. The magnitude of the charge / discharge power to be allocated to the power converter 16 performing overload control may be changed for each power converter 16 performing overload control, for example, depending on the magnitude of the equipment rated power of the power converter 16 performing overload control, the magnitude of the set rated power, and the remaining capacity of the connected storage battery 4.

[0054] The charge / discharge command value for overload control can be arbitrarily set so that the total charge / discharge power output from the remaining power converters 16 equals the required charge / discharge power. More specifically, the control unit 42 performs overload control when a set rated power is set for multiple power converters 16, some of the multiple power converters 16 malfunction and the required charge / discharge power is greater than the sum of the set rated powers of the remaining power converters 16, by setting a charge / discharge command value equal to or greater than the set rated power for at least some of the remaining power converters 16.

[0055] Furthermore, the required charge and discharge power is set according to, for example, the rate of change of the total power output from each power converter 14 to the power system PS. For example, if the total power increases beyond a certain rate of change standard, the amount of power exceeding the standard is set as the required charge power. Conversely, if the total power decreases beyond a certain rate of change standard, the amount of power exceeding the standard is set as the required discharge power. In this case, the control unit 42 sets the required charge and discharge power based, for example, status monitoring information of each power converter 14.

[0056] For example, if the solar power generation system 10 is a self-consumption type system, the required charging and discharging power is set according to the difference between the total power output from each power converter 14 to the power grid PS and the power required by the load. For example, if the total power is greater than or equal to the power required by the load, the difference in power magnitude is set as the required charging power. Conversely, if the total power is less than the power required by the load, the difference in power magnitude is set as the required discharging power.

[0057] Thus, the required charging and discharging power is set appropriately according to the system configuration of the solar power generation system 10 (battery storage system).

[0058] The control unit 42 detects abnormal shutdowns of multiple power converters 16 based on status monitoring information of each power converter 16. When the control unit 42 detects an abnormal shutdown of some of the multiple power converters 16, it determines whether the conditions for performing overload control are met, and if the conditions are met, it performs overload control on at least some of the remaining power converters 16.

[0059] The conditions for performing overload control include, for example, four conditions: Condition 1 to Condition 4. Condition 1 is that the charge / discharge power required for the remaining power converter 16 is less than or equal to the maximum charge / discharge power of the remaining power converter 16. In other words, Condition 1 is that the charge / discharge power required for the remaining power converter 16 is less than or equal to the equipment rated power of the remaining power converter 16.

[0060] The second condition is that the remaining capacity of the battery 4 connected to the remaining power converter 16 is equal to or greater than the charge / discharge power required for the remaining power converter 16. More specifically, when the remaining power converter 16 is to perform a charging operation, the amount of power that can be charged into the battery 4 connected to the remaining power converter 16 is equal to or greater than the charge power required for the remaining power converter 16, and when the remaining power converter 16 is to perform a discharging operation, the amount of power that can be discharged from the battery 4 connected to the remaining power converter 16 is equal to or greater than the discharge power required for the remaining power converter 16. In other words, the second condition is that, at the point in time when overload control becomes necessary, the remaining capacity of the battery 4 connected to the remaining power converter 16 is in an overloaded state.

[0061] The third condition is that the remaining capacity (SOC) of the battery 4 connected to the remaining power converter 16 is within the range of the remaining capacity that allows for operation.

[0062] The fourth condition is that the operating temperature and voltage of the battery 4 connected to the remaining power converter 16 are within the operating range of the battery 4.

[0063] When the control unit 42 detects an abnormal shutdown of some of the multiple power converters 16, and satisfies the four conditions described above (the first to fourth conditions), it performs overload control on at least some of the remaining power converters 16.

[0064] However, the conditions for performing overload control do not necessarily have to satisfy all four conditions from the first to the fourth. For example, instead of replacing all of the charging and discharging power of the abnormally stopped power converter 16 with the remaining power converters 16, it is possible to replace a portion of the charging and discharging power of the abnormally stopped power converter 16 with the remaining power converters 16 within the operational range in order to suppress the output fluctuations of the solar power generation system 10 as much as possible. In this case, for example, the first and second conditions do not necessarily have to be satisfied.

[0065] Furthermore, the third condition does not necessarily have to be met, for example, if control is performed to ensure that the remaining capacity of the battery 4 does not fall outside the range of the remaining capacity that can be operated. For example, if the device is operating at or below its rated power, the fourth condition does not necessarily have to be met if there is a low possibility of abnormalities occurring in the operating temperature and voltage of the battery 4.

[0066] However, as described above, by performing overload control when all four conditions from the first to the fourth are met, it is possible to prevent, for example, the overload control from placing an excessive load on the remaining power converter 16, which could cause an abnormality in the remaining power converter 16.

[0067] Furthermore, the conditions for performing overload control are not limited to the four conditions listed above, but may include other conditions as well. The conditions for performing overload control are not limited to the above, but may include any conditions necessary for proper overload control.

[0068] Figures 2 and 3 are flowcharts schematically illustrating an example of the operation of a solar power generation system according to the embodiment. As shown in Figures 2 and 3, the information acquisition unit 40 of the output control device 12 acquires information on output control values, measured values, and status monitoring information for each power converter 14 and 16. The information acquisition unit 40 acquires information on measured values ​​from the power meter 26, for example (step S101 in Figure 2). The information acquisition unit 40 acquires status monitoring information from each power converter 14 and 16 by periodically communicating with each power converter 14 and 16, for example. The information acquisition unit 40 acquires information on output control values ​​from the power server by communicating with the power server, for example. The information acquisition unit 40 also receives input of the command value of the set rated power from the power server by communicating with the power server, for example.

[0069] In Figure 2, for convenience, each power converter 14 is labeled as "Solar PCS," "Solar PCS_A," and "Solar PCS_N." Similarly, in Figure 3, for convenience, each power converter 16 is labeled as "Battery PCS," "Battery PCS_A," and "Battery PCS_N."

[0070] The control unit 42 of the output control device 12 determines, for example, whether the power output from the solar power generation system 10 to the power grid PS deviates from the standard rate of change, based on information on the output control value, information on the measured value, and status monitoring information of each power converter 14, 16, and also determines whether it is necessary to control the output of each power converter 14 and to charge / discharge each power converter 16 in addition to the deviation from the rate of change (step S102 in Figure 2).

[0071] After making the above determination, the control unit 42 executes the control flow for each power converter 14 and the control flow for each power converter 16.

[0072] In the control flow of each power converter 14, the control unit 42 first determines whether the rate of change deviates from the standard (step S103 in Figure 2).

[0073] If the control unit 42 determines that the rate of change has not deviated from the standard, it then determines whether there are any other conditions that require output control besides the deviation in the rate of change (step S104 in Figure 2). Conditions that require output control besides the deviation in the rate of change include, for example, conditions for limiting the output from multiple power converters 14 and 16 to the power system PS side based on information on the output control value. However, the conditions that require output control besides the deviation in the rate of change are not limited to these, and may be any conditions that require output control.

[0074] If the control unit 42 determines that there are no conditions other than deviations in the rate of change that require output control, it calculates a power generation command value that does not require output control and transmits the calculated power generation command value to each power converter 14 (step S105 in Figure 2). In other words, the power generation command value that does not require output control is a power generation command value that outputs 100% of the power generated by the solar panels 2 to the power grid PS side.

[0075] If the control unit 42 determines that there are conditions other than deviations in the rate of change that require output control, it calculates a power generation command value corresponding to the determined conditions (step S106 in Figure 2).

[0076] If the control unit 42 determines in step S103 that the rate of change has deviated from the reference, it then determines whether there are any other conditions besides the deviation in the rate of change that require output control (step S107 in Figure 2).

[0077] If the control unit 42 determines that there are no other conditions requiring output control besides deviations in the rate of change, it calculates a power generation command value corresponding to the condition of deviation in the rate of change (step S108 in Figure 2).

[0078] If the control unit 42 determines that there are conditions other than deviations in the rate of change that require output control, it calculates a power generation command value corresponding to the condition with the highest priority among the determined conditions and the conditions for deviations in the rate of change (step S109 in Figure 2).

[0079] The control unit 42 calculates the output-controlled power generation command value in one of steps S106, S108, or S109, and then transmits the calculated power generation command value to each power converter 14 (step S110 in Figure 2).

[0080] Each power converter 14 operates the converter 30 to output power to the power grid PS side in an amount corresponding to the generated power command value received from the output control device 12 (steps S111a to S111n in Figure 2).

[0081] Furthermore, each power converter 14 operates the converter 30 to output power corresponding to the generated power command value to the power grid PS side, and transmits status monitoring information corresponding to the operation of the converter 30 to the output control device 12 (steps S112a to S112n in Figure 2).

[0082] In the control flow of each power converter 16, the control unit 42 first determines whether the rate of change deviates from the standard (step S120 in Figure 3).

[0083] If the control unit 42 determines that the rate of change has not deviated from the standard, it then determines whether there are any other conditions that require charging or discharging besides the deviation in the rate of change (step S121 in Figure 3). Conditions that require charging or discharging besides the deviation in the rate of change include, for example, the command value of the set rated power input from a power server, and the charging or discharging conditions related to the protection of each battery 4. Conditions that require charging or discharging related to the protection of each battery 4 include, for example, charging or discharging conditions to eliminate imbalances in the remaining capacity of each battery 4, and charging or discharging conditions to eliminate excessive decreases or increases in the remaining capacity of each battery 4. However, the conditions that require charging or discharging besides the deviation in the rate of change are not limited to these, and may be any conditions that require charging or discharging.

[0084] If the control unit 42 determines that there are no conditions other than deviations in the rate of change that necessitate charging or discharging, it will not perform charging or discharging (step S122 in Figure 3). In other words, if the control unit 42 determines that there are no conditions other than deviations in the rate of change that necessitate charging or discharging, it will calculate a charge / discharge command value that will not perform charging or discharging (a charge / discharge command value that sets the magnitude of power output from each power converter 16 to 0), and transmit the calculated charge / discharge command value to each power converter 16.

[0085] If the control unit 42 determines that there are conditions other than deviations in the rate of change that require output control, it calculates a charge / discharge command value corresponding to the determined conditions (step S123 in Figure 3).

[0086] If the control unit 42 determines in step S120 that the rate of change has deviated from the standard, it then determines whether or not there is a power converter 16 that has stopped abnormally based on the status monitoring information of each power converter 16 (step S124 in Figure 3).

[0087] If the control unit 42 determines that there are no power converters 16 that have stopped abnormally, it then determines whether there are any conditions other than deviations in the rate of change that require charging or discharging (step S125 in Figure 3).

[0088] If the control unit 42 determines that there are no other conditions requiring charging or discharging besides a deviation in the rate of change, it calculates a charge / discharge command value corresponding to the condition of deviation in the rate of change (step S126 in Figure 3).

[0089] If the control unit 42 determines that there are conditions other than deviations in the rate of change that require charging or discharging, it calculates a charge / discharge command value corresponding to the condition with the highest priority among the determined conditions and the conditions for deviations in the rate of change (step S127 in Figure 3).

[0090] The control unit 42 calculates a plurality of charge / discharge command values ​​corresponding to each power converter 16 in one of steps S123, S126, or S127, and then transmits the calculated plurality of charge / discharge command values ​​to each power converter 16 (step S128 in Figure 3). In this case, the control unit 42 calculates a plurality of charge / discharge command values ​​using the maximum output of the charge / discharge power output from each power converter 16 as the preset rated power, and transmits the calculated plurality of charge / discharge command values ​​to each power converter 16.

[0091] If the control unit 42 determines in step S124 that there is a power converter 16 that has stopped abnormally, it then determines whether or not the conditions for overload control are met (step S129 in Figure 3).

[0092] If the control unit 42 determines that the conditions for overload control are not met, it executes the process in step S125. Therefore, in this case, even if there is a power converter 16 that has stopped abnormally, a charge / discharge command value with the maximum output set to the rated power is transmitted to the remaining power converters 16.

[0093] If the control unit 42 determines that the conditions for overload control are met, it then determines whether there are any other conditions other than deviations in the rate of change that require charging or discharging (step S130 in Figure 3).

[0094] If the control unit 42 determines that there are no other conditions requiring charging or discharging besides a deviation in the rate of change, it calculates the charge / discharge command value for overload control corresponding to the condition of deviation in the rate of change (step S131 in Figure 3).

[0095] If the control unit 42 determines that there are conditions other than deviations in the rate of change that require charging or discharging, it calculates the charge / discharge command value for overload control corresponding to the condition with the highest priority among the determined conditions and the conditions for deviations in the rate of change (step S132 in Figure 3).

[0096] In step S131 or S132, the control unit 42 calculates a plurality of charge / discharge command values ​​corresponding to each power converter 16, and then transmits the calculated plurality of charge / discharge command values ​​to each power converter 16 (step S133 in Figure 3). In this case, the control unit 42 calculates a plurality of charge / discharge command values ​​to set a charge / discharge command value equal to or greater than the set rated power for at least some of the remaining power converters 16 as necessary, and transmits the calculated plurality of charge / discharge command values ​​to each power converter 16.

[0097] Each power converter 16 operates the converter 34 to output power to the battery 4 side or the power grid PS side in an amount corresponding to the charge / discharge command value received from the output control device 12 (steps S134a to S134n in Figure 3).

[0098] Furthermore, each power converter 16 operates the converter 34 to output power of an magnitude corresponding to the charge / discharge command value to the battery 4 side or the power grid PS side, and transmits status monitoring information corresponding to the operation of the converter 34 to the output control device 12 (steps S135a to S135n in Figure 3).

[0099] As described above, in the photovoltaic power generation system 10 and output control device 12 according to this embodiment, when the control unit 42 of the output control device 12 has set a set rated power for a plurality of power converters 16, and some of the plurality of power converters 16 stop abnormally, and the amount of required charge / discharge power is greater than the sum of the set rated powers of the remaining power converters 16, the control unit 42 of the output control device 12 performs overload control to set a charge / discharge command value equal to or greater than the set rated power for at least some of the remaining power converters 16.

[0100] As a result, in the solar power generation system 10 and output control device 12 according to this embodiment, even if some of the multiple power converters 16 malfunction, it is easier to secure the necessary charging and discharging power compared to the case where the remaining power converters 16 continue to operate at their set rated power.

[0101] Furthermore, in the photovoltaic power generation system 10 and output control device 12 according to this embodiment, when the control unit 42 of the output control device 12 detects an abnormal shutdown of some of the multiple power converters 16, it determines whether the conditions for performing overload control are met, and if the conditions are met, it performs overload control on at least some of the remaining power converters 16. This makes it possible to prevent, for example, excessive load being placed on the remaining power converters 16 by overload control, which could cause abnormalities in the remaining power converters 16.

[0102] In the above embodiment, a photovoltaic power generation system 10 is shown as an example of a distributed power source system, using solar panels 2 as the distributed power source. The distributed power source is not limited to solar panels 2, but may also be, for example, a wind turbine or a geothermal generator. The distributed power source may be any power source capable of supplying electricity. The electricity supplied by the distributed power source is not limited to DC power, but may also be AC ​​power, etc. The distributed power source system is not limited to the photovoltaic power generation system 10, but may be any system using any distributed power source.

[0103] Furthermore, the above embodiment shows an example in which the battery storage system is introduced into the solar power generation system 10 (distributed power supply system). In other words, the output control device 12 is used in common with both the battery storage system and the distributed power supply system. The battery storage system is not limited to this and may be provided separately from the distributed power supply system. The battery storage system may be, for example, a system that is independently connected to the power grid PS and performs charging and discharging to suppress fluctuations in the voltage (effective value) of the power grid PS. In this case, the multiple power converters 16 charge the multiple batteries 4 based on the power of the power grid PS and discharge the power from the multiple batteries 4 to the power grid PS. The configuration of the battery storage system may be any configuration that includes at least the output control device 12 and the multiple power converters 16.

[0104] This embodiment includes the following aspects. (Note 1) An output control device that controls the charging and discharging operations of multiple storage batteries by multiple power converters, An information acquisition unit acquires status monitoring information including information on the magnitude of the charging and discharging power of the multiple power converters, information on the remaining capacity of the multiple batteries, and information on abnormalities in the multiple power converters. A control unit that, based on the status monitoring information, calculates multiple charge / discharge command values ​​representing the magnitude of power to be output from each of the multiple power converters, and transmits each of the calculated multiple charge / discharge command values ​​to each of the multiple power converters corresponding to it, thereby causing each of the multiple power converters to output power of a magnitude corresponding to the multiple charge / discharge command values, Equipped with, The control unit, For the aforementioned multiple power converters, a set rated power lower than the equipment rated power, which represents the amount of power that the device can output, is set. Based on the information regarding the abnormality included in the status monitoring information, the abnormal shutdown of the multiple power converters is detected. An output control device that performs overload control to set a charge / discharge command value equal to or greater than the set rated power for at least some of the remaining power converters when, while the set rated power is set for the plurality of power converters, some of the plurality of power converters stop abnormally and the amount of required charge / discharge power is greater than the sum of the set rated powers of the remaining power converters.

[0105] (Note 2) The output control device according to Appendix 1, wherein the control unit, upon detecting an abnormal shutdown of some of the multiple power converters, determines whether the conditions for performing the overload control are met, and if the conditions are met, performs the overload control on at least some of the remaining power converters.

[0106] (Note 3) The output control device according to Appendix 2, wherein the conditions for performing the overload control include the condition that the charge / discharge power required for the remaining power converter is less than or equal to the maximum charge / discharge power of the remaining power converter.

[0107] (Note 4) The output control device according to Appendix 2 or 3, wherein the conditions for performing the overload control include the condition that the remaining capacity of the battery connected to the remaining power converter is equal to or greater than the charge / discharge power required for the remaining power converter.

[0108] (Note 5) The output control device according to any one of the appendices 2 to 4, wherein the conditions for performing the overload control include the condition that the remaining capacity of the battery connected to the remaining power converter is within the range of the remaining capacity that can be operated.

[0109] (Note 6) The output control device according to any one of Appendix 2 to 5, wherein the conditions for performing the overload control include the condition that the operating temperature and voltage of the battery connected to the remaining power converter are within the operating range of the battery.

[0110] (Note 7) Multiple power converters connected to multiple storage batteries, which charge and discharge the multiple storage batteries, An output control device that controls the charging and discharging operations of the multiple storage batteries by the multiple power converters, Equipped with, The output control device is An information acquisition unit acquires status monitoring information including information on the magnitude of the charging and discharging power of the multiple power converters, information on the remaining capacity of the multiple batteries, and information on abnormalities in the multiple power converters. A control unit that, based on the status monitoring information, calculates multiple charge / discharge command values ​​representing the magnitude of power to be output from each of the multiple power converters, and transmits each of the calculated multiple charge / discharge command values ​​to each of the multiple power converters corresponding to it, thereby causing each of the multiple power converters to output power of a magnitude corresponding to the multiple charge / discharge command values, It has, The control unit, For the aforementioned multiple power converters, a set rated power lower than the equipment rated power, which represents the amount of power that the device can output, is set. Based on the information regarding the abnormality included in the status monitoring information, the abnormal shutdown of the multiple power converters is detected. A battery storage system that performs overload control to set a charge / discharge command value equal to or greater than the set rated power for at least some of the remaining power converters when, while the set rated power is set for the plurality of power converters, some of the plurality of power converters malfunction and the amount of required charge / discharge power is greater than the sum of the set rated powers of the remaining power converters.

[0111] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols]

[0112] 2…Solar panels (distributed power source), 4…Storage battery, 10…Solar power generation system (distributed power source system, storage battery system), 12…Output control device, 14, 16…Power converter, 18, 20, 22…Transformer, 24…Substation equipment, 26…Power meter, 30…Converter, 32…Communicator, 34…Converter, 36…Communicator, 40…Information acquisition unit, 42…Control unit, CP…Interconnection point, PS…Power grid

Claims

1. An output control device that controls the charging and discharging operations of multiple storage batteries by multiple power converters, An information acquisition unit acquires status monitoring information including information on the magnitude of the charging and discharging power of the multiple power converters, information on the remaining capacity of the multiple batteries, and information on abnormalities in the multiple power converters. A control unit that, based on the status monitoring information, calculates multiple charge / discharge command values ​​representing the magnitude of power to be output from each of the multiple power converters, and transmits each of the calculated multiple charge / discharge command values ​​to each of the multiple power converters corresponding to it, thereby causing each of the multiple power converters to output power of a magnitude corresponding to the multiple charge / discharge command values, Equipped with, The control unit, For the aforementioned multiple power converters, a set rated power lower than the equipment rated power, which represents the amount of power that the device can output, is set. Based on the information regarding the abnormality included in the status monitoring information, the abnormal shutdown of the multiple power converters is detected. An output control device that performs overload control to set a charge / discharge command value equal to or greater than the set rated power for at least some of the remaining power converters when, while the set rated power is set for the plurality of power converters, some of the plurality of power converters stop abnormally and the amount of required charge / discharge power is greater than the sum of the set rated powers of the remaining power converters.

2. The output control device according to claim 1, wherein the control unit, upon detecting an abnormal shutdown of some of the plurality of power converters, determines whether the conditions for performing the overload control are met, and if the conditions are met, performs the overload control on at least some of the remaining power converters.

3. The output control device according to claim 2, wherein the conditions for performing the overload control include the condition that the charge / discharge power required for the remaining power converter is less than or equal to the maximum charge / discharge power of the remaining power converter.

4. The output control device according to claim 2, wherein the conditions for performing the overload control include the condition that the remaining capacity of the battery connected to the remaining power converter is equal to or greater than the charge / discharge power required for the remaining power converter.

5. The output control device according to claim 2, wherein the conditions for performing the overload control include the condition that the remaining capacity of the battery connected to the remaining power converter is within the range of the remaining capacity that can be operated.

6. The output control device according to claim 2, wherein the conditions for performing the overload control include the condition that the operating temperature and voltage of the battery connected to the remaining power converter are within the operating range of the battery.

7. Multiple power converters connected to multiple storage batteries, which charge and discharge the multiple storage batteries, An output control device that controls the charging and discharging operations of the multiple storage batteries by the multiple power converters, Equipped with, The output control device is An information acquisition unit acquires status monitoring information including information on the magnitude of the charging and discharging power of the multiple power converters, information on the remaining capacity of the multiple batteries, and information on abnormalities in the multiple power converters. A control unit that, based on the status monitoring information, calculates multiple charge / discharge command values ​​representing the magnitude of power to be output from each of the multiple power converters, and transmits each of the calculated multiple charge / discharge command values ​​to each of the multiple power converters corresponding to it, thereby causing each of the multiple power converters to output power of a magnitude corresponding to the multiple charge / discharge command values, It has, The control unit, For the aforementioned multiple power converters, a set rated power lower than the equipment rated power, which represents the amount of power that the device can output, is set. Based on the information regarding the abnormality included in the status monitoring information, the abnormal shutdown of the multiple power converters is detected. A battery storage system that performs overload control to set a charge / discharge command value equal to or greater than the set rated power for at least some of the remaining power converters when, while the set rated power is set for the plurality of power converters, some of the plurality of power converters malfunction and the amount of required charge / discharge power is greater than the sum of the set rated powers of the remaining power converters.

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