Distributed energy storage system, control device, and energy storage device

Abstract

This system provides a distributed energy storage device configuration that enables planned adjustment of electricity supply and demand. [Solution] The control device according to the embodiment is a device that sets a target value for power exchange with a feeder line and comprehensively controls a plurality of energy storage devices that charge and discharge batteries based on the target value, and includes a function to receive first control information regarding the charging and discharging of a distributed energy storage device system including a plurality of distributed energy storage devices, based on a power supply and demand plan for a system that converts power supplied from the commercial power grid and supplies power to the feeder line, and a function to generate and transmit second control information regarding the charging and discharging of an energy storage device to at least one of the plurality of energy storage devices based on the first control information.

Description

[Technical Field]

[0001] Embodiments of the present invention relate to a control device and an energy storage device. [Background technology]

[0002] To ensure a stable power supply, it is essential to secure supply and demand adjustment capacity, which controls frequency and balances supply and demand within the power supply area. Supply and demand adjustment capacity is the power supply capacity that matches supply (generation) with the ever-changing power demand (consumption). In recent years, a supply and demand adjustment market has been established that enables the trading of supply and demand adjustment capacity. Various methods have been proposed to provide supply and demand adjustment capacity in accordance with the power supply and demand plans required in the supply and demand adjustment market.

[0003] With the spread of distributed power sources such as solar and wind power, Virtual Power Plants (VPPs) are attracting attention as a method for providing supply and demand adjustment capabilities. VPPs provide supply and demand adjustment capabilities by integrating and controlling distributed power sources, including renewable energy facilities and storage batteries, and systematically adjusting stored energy. The application fields of VPPs are diverse, and their application has also been proposed in the electric railway sector.

[0004] Here, one known method of supplying power to railway vehicles in electric railways is the DC power supply system. DC power supply systems may be connected to electric railway substations that include batteries or energy storage elements (hereinafter simply referred to as "batteries") to counteract regenerative failure or overhead line voltage drops. By charging and discharging the batteries, the regenerative rate is improved and the overhead line voltage is stabilized.

[0005] Furthermore, regarding the adjustment of power supply and demand in the electric railway sector, attempts have been reported to reduce peak power by supplying power from secondary batteries connected to the feeder lines. The secondary batteries are connected directly to the overhead lines, or to the overhead lines via converters such as choppers, and are charged and discharged in response to decreases or increases in the overhead line voltage. Attempts have also been reported to connect storage batteries to the feeder lines via converters and discharge the storage batteries by increasing the output voltage.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Non-Patent Documents

[0007]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, simply performing charge and discharge of a storage battery in response to a decrease or increase in the voltage of a power supply line cannot provide a system for performing planned power supply and demand adjustment. Also, when connecting a storage battery to a power supply line without using a power converter, it is impossible to control the charge and discharge power or the stored energy of the storage battery. The charge and discharge characteristics of a storage battery connected to a power supply line without using a power converter are uniquely determined by the difference between the storage battery voltage and the output voltage of the power supply rectifier. Therefore, it is difficult to provide a system for performing planned power supply and demand adjustment and stabilizing an AC power distribution system.

[0009]

[0010] Embodiments of the present invention have been made in view of the above circumstances, and an object thereof is to provide a distributed storage device system capable of performing planned power supply and demand adjustment.

Means for Solving the Problems

[0011] The control device according to the embodiment is a device that sets a target value for power exchange with a feeder line and comprehensively controls a plurality of energy storage devices that charge and discharge batteries based on the target value, and includes a function to receive first control information regarding the charging and discharging of a distributed energy storage device system including a plurality of distributed energy storage devices, based on a power supply and demand plan for a system that converts power supplied from the commercial power grid and supplies power to the feeder line, and a function to generate and transmit second control information regarding the charging and discharging of the energy storage device to at least one of the plurality of energy storage devices based on the first control information. [Brief explanation of the drawing]

[0012] [Figure 1] Figure 1 is a schematic diagram showing one example configuration of a distributed energy storage device system according to the first embodiment. [Figure 2] Figure 2 is a diagram illustrating an example of charge and discharge control according to the feed voltage in a distributed energy storage device system according to the first embodiment. [Figure 3] Figure 3 is a diagram showing the relationship between the charge rate and the charge / discharge start voltage for adjusting the State of Charge (SOC) to a certain range in a distributed energy storage device system according to the first embodiment. [Figure 4] Figure 4 shows an example of control in which the State of Charge (SOC) is changed by changing the discharge characteristics in a distributed energy storage device system according to the first embodiment. [Figure 5] Figure 5 shows an example of control that changes the State of Charge (SOC) by changing the charging characteristics in a distributed energy storage device system according to the first embodiment. [Figure 6] Figure 6 is a schematic diagram showing a modified example of the distributed energy storage device system according to the first embodiment. [Figure 7] Figure 7 is a schematic diagram showing a first configuration example of a distributed energy storage device system according to the second embodiment. [Figure 8] Figure 8 shows an example of power command value generation in a distributed energy storage device system according to the second embodiment. [Figure 9]Figure 9 is a schematic diagram showing a second configuration example of a distributed energy storage device system according to the second embodiment. [Figure 10] Figure 10 is a schematic diagram showing a modified example of the distributed energy storage device system according to the second embodiment. [Figure 11] Figure 11 is a schematic diagram showing one example configuration of a distributed energy storage device system according to the third embodiment. [Figure 12] Figure 12 shows a modified example of a power storage device in a distributed power storage device system according to the third embodiment. [Figure 13] Figure 13 is a schematic diagram showing one example configuration of a distributed energy storage device system according to the fourth embodiment. [Modes for carrying out the invention]

[0013] Embodiments relating to this invention will be described below with reference to the drawings. Hereafter, elements identical or similar to those already described will be denoted by the same or similar reference numerals, and redundant descriptions will generally be omitted. For example, when multiple identical or similar elements exist, a common reference numeral may be used to describe them without distinction, or a sub-number may be used in addition to the common reference numeral to describe them separately.

[0014] (First Embodiment) (1-1) Configuration examples and operation examples Figure 1 is a schematic diagram showing one example configuration of a distributed energy storage system according to the first embodiment. The distributed energy storage system 100 according to the first embodiment is used together with a DC power supply system that supplies power to vehicles such as electric railways or monorails (hereinafter referred to as "electric vehicles"). The DC power supply system comprises an AC power line 11, a substation 4, a power supply line 8, an electric vehicle 5, and a return line 9. The distributed energy storage system 100 comprises a plurality of energy storage devices 20 distributed with respect to the DC power supply system, and a higher-level control device 6.

[0015] AC system 11 is a commercial power system that supplies three-phase AC power to substation 4. Substation 4 is a feeder substation and is located at intervals of, for example, 5 to 10 km. Substation 4 receives three-phase AC power from AC system 11, converts the three-phase AC to DC power (for example, 1,650V) via transformers and rectifiers (not shown), and supplies power to feeder lines 8.

[0016] The feeder line 8 supplies power to the electric vehicle 5. The electric vehicle 5 is a vehicle capable of running by receiving power output from the substation 4 via the feeder line 8, such as an electric train. The return line 9 is a conductor through which the return current flows, and is, for example, the rail on which the electric train 5 runs. The circuit in which the power supplied from the substation 4 is consumed by the electric train 5 (load) via the feeder line 8 and returns to the substation 4 again via the return line 9 is also called the feeder circuit.

[0017] Multiple energy storage devices 20 are distributed at arbitrary intervals and each is connected to a feeder line 8 and a return line 9. Each energy storage device 20 comprises a battery 1, a power converter 2, and a control unit 3.

[0018] The battery 1 is connected to the power converter 2 and can be charged and discharged between the power converter 2 and the feeder line 8. The battery 1 is an energy storage module equipped with a battery pack containing multiple rechargeable battery cells, such as lithium-ion batteries, nickel-metal hydride batteries, or lead-acid batteries, and a cell monitoring unit (CMU). The battery pack contains, for example, 24 battery cells connected in 2 parallel and 12 series configurations of 20Ah battery cells. The CMU measures the voltage and temperature of each battery cell and can notify the control unit 3 of the measurement results via a communication protocol such as CAN (Controller Area Network). The CMU also receives commands from the control unit 3 and performs cell balancing to achieve the voltage instructed by the control unit 3. Cell balancing refers to adjusting the voltage to the instructed level by discharging cells with high voltages. The battery 1 may be replaced with other energy storage devices or systems, such as electric double-layer capacitors, flywheels, or hydroelectric power generation equipment.

[0019] The power converter 2 is connected between the battery 1 and the power line 8, and between the battery 1 and the return line 9. The power converter 2 exchanges power between the battery 1 and the power line 8, and controls the charging and discharging between the battery 1 and the power circuit. For example, when connecting the battery 1 to a DC power supply circuit, the power converter 2 includes a DC / DC converter. However, the power converter 2 may use any converter depending on the type of energy storage medium and the power circuit. The power converter 2 also includes a current limiter that controls the limit value of the charging and discharging current.

[0020] The control unit 3 controls the operation of the energy storage device 20. The control unit 3 gives commands to the power converter 2 regarding the charging and discharging of the battery 1. The control unit 3 includes a processor such as a CPU (Central Processing Unit) and memory. The control unit 3 realizes various functions by executing a program. Some of the functions of the control unit 3 may be realized by an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array), etc. The control unit 3 may include a Battery Management Unit (BMU). The control unit 3 sets a target value related to the power supply and demand balance in the feeder line 8 and outputs commands to the power converter 2 regarding the charging and discharging of the battery 1 based on that target value.

[0021] More specifically, the control unit 3 monitors the cell voltage and temperature of the battery 1 and calculates the State of Charge (SOC) of the battery 1. The control unit 3 also monitors the voltage of the feeder line 8, for example, via the power converter 2. The control unit 3 sets target values ​​for power transfer between the feeder line 8 and the distributed energy storage system 100, calculates power command values ​​for charging and discharging the battery 1 based on the set target values, and outputs the power command values ​​to the power converter 2.

[0022] The control unit 3 is also capable of bidirectional communication with the higher-level control unit 6 via the transmission line 7. The transmission line 7 is constructed as a bidirectional double-ring type transmission line, for example, using a token ring with twisted-pair cables, so that communication can continue even if one part of the line is broken. Other transmission methods may be used for communication between the control unit 3 and the higher-level control unit 6.

[0023] The higher-level control unit 6 provides integrated control of the operation of multiple distributed energy storage devices 20. The higher-level control unit 6 transmits information bidirectionally to each energy storage device 20 via the transmission line 7. The higher-level control unit 6 also includes a processor and memory, and implements various functions by executing programs. Some of the functions of the higher-level control unit 6 may also be implemented by an ASIC, PLD, or FPGA. The higher-level control unit 6 manages the power value required for the entire distributed energy storage device system 100 as a target power value, and assigns the target power value to the multiple energy storage devices 20 (for example, three energy storage devices 20 in Figure 1). The target power value may be received from a control device even higher than the higher-level control unit 6, or it may be input to the higher-level control unit 6 by a human system. Based on the target power value assigned to each energy storage device 20, the higher-level control unit 6 generates control information including power command values ​​for charging and discharging each battery 1, and transmits the control information to the control unit 3 of each energy storage device 20.

[0024] The distributed energy storage system 100 controls power supply and demand adjustment based on a power supply and demand plan set between the power supply system, including the power lines 8 and the commercial power grid, and the distributed energy storage system 100. The supply and demand plan includes information such as charging or discharging at a specific time on a specific day, and can also be referred to as a power generation plan, demand plan, or supply plan. The set supply and demand plan is stored in the higher-level control unit 6. Based on the supply and demand plan, the higher-level control unit 6 generates control information (first control information) regarding the charging and discharging of the rechargeable battery 1 and transmits the control information to each of the multiple energy storage devices 20. As a result, the higher-level control unit 6 performs overall control based on a target power value or target SOC that should be managed for the entire distributed energy storage system 100. Since energy can be obtained by integrating power over time, controlling power effectively allows for energy control. Following the target power ultimately leads to the realization of the target SOC. The supply and demand plan can also be described as information on when and how to change the discharge start voltage or charge start voltage. The supply and demand plan may be stored in each energy storage device 20 in addition to the higher-level control device 6. The higher-level control device 6 may generate control information so that each energy storage device 20 achieves its assigned target power value, or it may generate control information so that each energy storage device 20 maintains a desired SOC state for the battery 1.

[0025] The control unit 3 of each energy storage device 20 sets target values ​​related to power transfer based on control information received from the higher-level control device 6. The control unit 3 may set the power command value or SOC value, etc., included in the control information received from the higher-level control device 6 as the target value, or it may calculate the target value based on the value included in the control information. The target value may include, for example, at least one of the following: a first voltage value representing a constant target voltage at which the voltage of the feeder line 8 should be maintained; a second voltage value representing the target voltage of the feeder line 8 at which charging to the battery 1 should begin; a third voltage value representing the target voltage of the feeder line 8 at which discharging from the battery 1 should begin; a charge / discharge power command value representing the target charge / discharge power of the battery 1; a first current value representing a charge current limit value that limits the charging current to the battery 1; or a second current value representing a discharge current limit value that limits the discharging current from the battery 1. Based on the set target value, the control unit 3 generates command values ​​related to the charging and discharging of the battery and outputs them to the power converter 2.

[0026] The higher-level control device 6 may transmit the charging / discharging start voltage or the charging / discharging current limit value as control information to the control unit 3 of each energy storage device 20. Each battery 1 of the multiple energy storage devices 20 distributed throughout the power supply system charges when the overhead line voltage rises and discharges when the overhead line voltage falls. In such a power supply system, when voltage control is performed so that the discharge voltage of the energy storage device 20 to the power supply circuit reaches a target voltage (for example, 1,650V), the power converter 2 increases the output voltage within a range that does not cause inconvenience to vehicles or substations, and then controls the discharge current so that the discharge current does not exceed a certain value (current control), thereby effectively enabling the discharge of the target power. Similarly, in the case of charging, the voltage is lowered and the charging current is limited so that the charging current does not exceed a certain value, thereby enabling charging of the target power. The control unit 3 can set the charging / discharging start voltage or the charging / discharging current limit value included in the control information received from the higher-level control device 6 as the target value.

[0027] The control unit 3 of each power storage device 20 feeds back the command value actually transmitted to the power converter 2 to the upper-level control device 6. The timing or time interval of the feedback may be set arbitrarily. The control unit 3 may also transmit other information including the temperature of the storage battery 1, the SOC of the storage battery 1, and the power value charged and discharged between the storage battery 1 and the power line 8 to the upper-level control device 6. The upper-level control device 6 receives, as feedback, the command value output from the control unit 3 to the power converter 2 from at least one of the plurality of power storage devices 20 arranged dispersedly, and based on the received command value and the set supply-demand plan, generates the following control information (second control information) regarding the charge and discharge of the storage battery 1, and can transmit it to the plurality of power storage devices 20.

[0028] As an example, the upper-level control device 6 calculates the deviation (difference) between the feedback received from the plurality of power storage devices 20 arranged dispersedly and the target power value or the target SOC, generates the following control information so as to reduce the deviation, and transmits it to each power storage device 20. For example, the upper-level control device 6 first determines the target power value W T for the entire power storage device dispersed arrangement system 100 based on the supply-demand plan, T and distributes the target power value W 11 , W 12 ,... W 1N )(where W T = W 11 + W 12 +... + W 1N ). The distribution of the target power value W T may be equal or unequal. The upper-level control device 6 generates first control information (CS 11 , CS 12 ,... CS 1N ) each including the distributed power values (W 11 , CS 12 ,... CS 1N ) and transmits it to each of the N power storage devices 20. The upper-level control device 6 that has received feedback from the N power storage devices 20 has the power command value output from the control unit 3 to the power converter 2 or the power value (WO 11 , WO 12 ,... WO1N The sum of ) (WO1=WO 11 +WO 12 +...+WO 1N )) and target power value W T The difference between (ΔW1=W) T The higher-level control device 6 calculates (WO1). The higher-level control device 6 then distributes this difference equally to each energy storage device 20, for example, and updates the command value to be included in the next control information (second control information). 21 ,W 22 ,...W 2N )(Here, W 21 =W 11 +ΔW1 / N,W 22 =W 12 +ΔW1 / N,...W 2N =W 1N +ΔW1 / N). The allocation of the difference may also be uneven. The higher-level control device 6 sets the updated command value (W 21 ,W 22 ,...W 2N ) each contains second control information (CS 21 CS 22 ,...CS 2N ) is generated and sent to each of the N energy storage devices 20. The reflection of feedback is not limited to the above example and may be reflected in a wide variety of ways.

[0029] The control information transmitted from the higher-level control device 6 to each control unit 3 may include commands to equalize the load in the multiple energy storage devices 20 under the monitoring of the higher-level control device 6 or the State of Charge (SOC) of each battery 1. The control information transmitted from the higher-level control device 6 to each control unit 3 may also include instructions to change the charging characteristics or discharging characteristics for the SOC of each battery 1. Based on the control information received from the higher-level control device 6, each control unit 3 sets a target value and generates a command to the power converter 2. The time interval between commands output from each control unit 3 to each power converter 2 is, for example, 25 to 100 milliseconds or 1 second. The distributed energy storage device system 100 can achieve the supply and demand adjustment required for the entire distributed energy storage device system 100 by supply and demand planning through the cooperation between the higher-level control device 6 and the control units 3 of the multiple distributed energy storage devices 20.

[0030] The number of energy storage devices 20 in the distributed energy storage device system 100 is not limited to the illustrated example. The higher-level control unit 6 can centrally control any number of energy storage devices 20. Similarly, the number and arrangement of substations 4 and electric vehicles 5 used with the distributed energy storage device system 100 are also just examples. The energy storage devices 20 may be located near the substations 4, in pairs with the substations 4, or independently of the substations 4. Batteries may be located instead of the substations 4.

[0031] Further details will be provided regarding a control example in the distributed energy storage device system 100 according to the first embodiment. Figure 2 is a diagram illustrating an example of charge / discharge control according to the feeder line voltage in the distributed energy storage device system 100 according to the first embodiment. The horizontal axis represents the feeder line voltage, and the vertical axis represents the charging current or discharging current. c1 V represents the charging start voltage. d1 V represents the discharge start voltage. The control unit 3 can control the charging and discharging of the storage battery 1 by generating charge and discharge commands using a table showing the relationship between the feeder line voltage and the charge / discharge current as shown in Figure 2 and outputting them to the power converter 2. According to Figure 2, the feeder line voltage is the charge start voltage V c1 When the voltage rises above this level, charging of battery 1 begins. The charging current increases as the feeder line voltage increases. However, a limit (maximum charging current) is set for the charging current. On the other hand, when the feeder line voltage rises above the discharge start voltage V d1 When the voltage drops below this level, discharge of battery 1 begins. The discharge current increases as the feeder line voltage decreases. However, a limit value (maximum discharge current) is also set for the discharge current. d1 Above, the charging start voltage V c1 Battery 1 will neither charge nor discharge in the following cases:

[0032] Here, in each of the distributed energy storage devices 20, the control unit 3 can control charging and discharging so that the voltage at the feeder connection point remains constant. Alternatively, in each of the distributed energy storage devices 20, the control unit 3 may control the voltage that the power converter 2 sends to the feeder line 8 (output voltage to the feeder circuit) to decrease in response to an increase in the discharge current from the battery 1, or it may control the voltage that the power converter 2 sends to the feeder line 8 (output voltage to the feeder circuit) to increase in response to an increase in the charging current to the battery 1.

[0033] Furthermore, the control unit 3 of each energy storage device 20 may control the voltage supplied to the feeder line 8 in accordance with the decrease in the State of Charge (SOC) of the battery 1. By controlling each energy storage device 20 to decrease the discharge voltage as the SOC of the battery 1 decreases, the energy storage device 20 with a high SOC of the battery 1 will bear more discharge power than the energy storage device 20 with a low SOC of the battery 1 when viewed as a whole in the distributed energy storage device system 100. This makes it possible to equalize the load sharing among the multiple energy storage devices 20 in the distributed energy storage device system 100.

[0034] The control unit 3 of each energy storage device 20 can control charging and discharging so that each battery 1 maintains a predetermined State of Charge (SOC). This can be achieved, for example, by a higher-level control device 6 setting a target value for SOC and transmitting it to the control unit 3 of each energy storage device 20, and the control unit 3 of each energy storage device 20 controlling the system to perform adjustable charging and discharging when the SOC of the battery 1 deviates from the target value. Alternatively, the higher-level control device 6 may not set a specific target value for SOC, and the control unit 3 of each energy storage device 20 may perform control to adjust the discharge start voltage or charge start voltage in response to the decrease in the SOC of the battery 1. The target value for SOC may also be a value received from a control device even higher than the higher-level control device 6, or a value input to the higher-level control device 6 by a human.

[0035] Figure 3 is a diagram showing the relationship between the state of charge (SOC) and the charge / discharge initiation voltage for adjusting the state of charge (SOC) of the battery 1 within a certain range in the distributed energy storage device system 100 according to the first embodiment. The horizontal axis represents SOC, and the vertical axis represents the discharge initiation voltage or charge initiation voltage. When the SOC decreases, the discharge initiation voltage or charge initiation voltage also decreases. The control unit 3 can control the charging and discharging of the battery 1 by generating charge / discharge commands using a table showing the relationship between SOC and charge / discharge initiation voltage as shown in Figure 3 and outputting them to the power converter 2.

[0036] While the control unit 3 of each energy storage device 20 is performing the above-described control, the higher-level control device 6 further outputs a charge or discharge command to each energy storage device 20. The charge or discharge command includes, for example, a command to change the charge characteristics or discharge characteristics with respect to the charge rate. Such a command may be sent from a control device in an even higher-level system than the higher-level control device 6, or it may be input to the higher-level control device 6 by a human system to cause it to output a charge or discharge command.

[0037] Figure 4 shows an example of control in the distributed energy storage device system 100 according to the first embodiment, in which the State of Charge (SOC) is changed by changing the discharge characteristics of the battery 1. The horizontal axis represents the State of Charge (SOC), and the vertical axis represents the discharge start voltage. Generally, the higher the SOC, the higher the voltage at which each energy storage device 20 starts discharging. The control unit 3 can adjust the supply and demand of power by changing the discharge characteristics as indicated by the arrow P. That is, in each energy storage device 20, the battery 1 normally operates in the A1 region, but operates in the B1 region in response to a command from the control unit 3. As a result, the battery 1 starts discharging at a high voltage in most SOC ranges. Consequently, energy equivalent to the difference in SOC between (A1-B1) is supplied from the battery 1 of each energy storage device 20 to the power supply circuit. When the SOC decreases, the voltage supplied decreases, and discharge stops. At this time, the maximum power value supplied from the battery 1 to the power supply circuit is the maximum value of the discharge start voltage V. max and the output current limit value I of the power converter 2 limitIt is determined by the product of the following. In this way, supply and demand can be adjusted by changing the command value of the discharge start voltage of the charge / discharge control. If you want to adjust the discharge power, the output current limit value I of the power converter 2 is limit You just need to change it.

[0038] The control unit 3 maintains a table that specifies the correspondence between the State of Charge (SOC) and the discharge start voltage, as shown in Figure 4, for example, and can switch the discharge characteristics to be used in response to commands from the higher-level control unit 6. Based on the specified discharge characteristics, the control unit 3 sets the discharge start voltage as a target value and generates a command to the power converter 2.

[0039] A similar scheme can be applied to charging. Figure 5 shows an example of control in the distributed energy storage device system 100 according to the first embodiment, in which the State of Charge (SOC) is changed by changing the charging characteristics of the battery 1. The horizontal axis represents the State of Charge (SOC), and the vertical axis represents the charging start voltage. Generally, the lower the SOC, the lower the voltage at which each energy storage device 20 starts charging. The control unit 3 can adjust the supply and demand of power by changing the charging characteristics as indicated by the arrow Q. That is, in each energy storage device 20, the battery 1 normally operates in the B2 region, but operates in the A2 region in response to a command from the control unit 3. As a result, the battery 1 starts charging at a low voltage for most of the SOC range. Consequently, energy equivalent to the difference in SOC between (A2-B2) is stored in the battery 1 of each energy storage device 20 from the power supply circuit. The maximum value of the charging power stored in each battery 1 from the power supply circuit is the charging start voltage V min and the current limit value I of power converter 2 limit It is determined by the product of the two. If you want to adjust the charging power, the current limit value I of power converter 2 is used. limit You just need to change it.

[0040] The control unit 3 maintains a table that specifies the correspondence between the State of Charge (SOC) and the charging start voltage, as shown in Figure 5, for example, and can switch the charging characteristics to be used in response to commands from the higher-level control unit 6. Based on the specified charging characteristics, the control unit 3 sets the charging start voltage as a target value and generates a command to the power converter 2.

[0041] The higher-level control device 6 may instruct each control unit 3 to switch the charge / discharge characteristics by transmitting a table specifying the charge / discharge characteristics, as shown in Figure 4 or Figure 5. Each control unit 3 may have multiple tables and switch between them in response to commands from the higher-level control device 6.

[0042] Note that the AC power supply circuit 11 in Figure 1 may be a single power system or it may be separated into multiple power systems.

[0043] (1-2) Effects When a battery storage device is deployed independently in a conventional power supply system, or when a centralized battery storage device is deployed, the discharge is affected by the impedance of the power supply circuit from the battery storage device to the load (electric vehicle). Discharge from the battery storage device to the power supply circuit causes the voltage at the connection point of the power supply circuit to which the battery storage device is connected to rise. As a result, the discharge current is suppressed and the discharge power decreases at the maximum voltage level at which continuous operation is possible before protective action is triggered (the limit voltage level before overvoltage occurs). On the other hand, during charging, the battery storage device is charged via the substation. Figure 1 shows a parallel power supply circuit that can supply power to the electric vehicle 5 from both substations 4. However, if one battery storage device 20 is charged with high power, the discharge power of the nearest substation 4 will increase, significantly lowering the power supply voltage and severely reducing the load output of substation 4.

[0044] According to the distributed energy storage system 100 of the first embodiment, multiple energy storage devices 20 are distributed across the power supply system. This distributed arrangement makes it possible to reduce the impedance of the power supply circuit from the energy storage devices 20 to the load of the electric vehicle 5. As a result, power can be supplied to loads at a greater distance than before. It also becomes possible to handle a wide range of loads, and high-output discharge operation is possible in the supply and demand adjustment of the energy storage devices 20. Even if a current sag occurs in one of the energy storage devices 20, the other energy storage devices 20 can compensate for the shortage. Therefore, the distributed energy storage system 100 as a whole can contribute to planned and stable power supply and demand adjustment. Similarly, charging 500kW with three energy storage devices 20 is less load on the control equipment than charging 500kW with one energy storage device 20. Therefore, by performing planned charging with the distributed energy storage devices 20, stable power supply and demand adjustment can be achieved.

[0045] Furthermore, by centrally controlling multiple energy storage devices 20 distributed within the power supply system, the supply and demand adjustment capabilities (power or energy quantity) of the energy storage devices 20 can be integrated and operated, resulting in the realization of a larger energy storage system plant.

[0046] The higher-level control unit 6 monitors the entire distributed energy storage system 100 and sends commands to each energy storage device 20 to perform coordinated control. The commands transmitted from the higher-level control unit 6 to the control unit 3 of each energy storage device 20 include, for example, a target power value assigned to each energy storage device 20. Each control unit 3 can obtain the target voltage of the feeder line by, for example, dividing the target power value by the limiter current. Each control unit 3 controls charging and discharging while comparing the voltage of the feeder line 8 with the target voltage. Each control unit 3 also returns information related to the actual charging and discharging to the higher-level control unit 6, for example, information indicating whether it was able to perform voltage control corresponding to the target power instructed by the higher-level control unit 6. The higher-level control unit 6 collects information related to the actual charging and discharging from the control unit 3 of each energy storage device 20 and sends commands to the control unit 3 so that the power supply and demand can be adjusted systematically for the entire distributed energy storage system 100.

[0047] The higher-level control device 6 may send a power command value to the control unit 3 of each energy storage device 20, and the control unit 3 may calculate a current limit value by dividing the received power command value by the charging / discharging voltage, and then send the current limit value from the control unit 3 to the power converter 2 to achieve control. This makes it possible for the control unit 3 of each energy storage device 20 to change the SOC of the battery 1 by controlling discharge or charging in response to a command from the higher-level control device 6, thereby enabling supply and demand adjustment for the entire distributed energy storage device system 100. Alternatively, the control unit 3 of each energy storage device 20 may have information such as a target power value, discharge start voltage, charge start voltage, or current limit value in advance.

[0048] Thus, the distributed energy storage system 100 according to the first embodiment operates as a whole: when there is insufficient power, it supplies stored energy (discharges), and when there is excess power, it stores power (charges). Therefore, the distributed energy storage system 100 as a whole can systematically adjust the supply and demand of power.

[0049] (1-3) Variations Figure 6 is a schematic diagram showing a modified example of the distributed energy storage system according to the first embodiment. Figure 6 is the same as Figure 1 except that the AC power grid 11 is separated in the power supply system. The distributed energy storage system 110 has the same configuration and operates similarly as the distributed energy storage system 100, so a detailed explanation is omitted. In other words, the distributed energy storage system 100 according to the first embodiment is also applicable when the substation 4 is supplied with power from separate and different AC power grids 11.

[0050] (Second Embodiment) (2-1) Configuration examples and operation examples The distributed energy storage system according to the second embodiment has the same configuration as the distributed energy storage system 100 according to the first embodiment, except that each energy storage device distributed to the power supply system performs self-end control. The differences from the first embodiment will be mainly described below.

[0051] Figure 7 is a schematic diagram showing a first configuration example of a distributed energy storage system according to the second embodiment. The distributed energy storage system 200 according to the second embodiment is used together with a DC power supply system, similar to the first embodiment. The DC power supply system comprises an AC system 11, a substation 4, a feeder line 8, an electric vehicle 5, and a return line 9. These are the same as the AC system 11, substation 4, feeder line 8, electric vehicle 5, and return line 9 of the DC power supply system described in relation to the first embodiment, so their description is omitted.

[0052] The distributed energy storage system 200 comprises a plurality of energy storage devices 21 distributed with respect to the power supply system. The multiple energy storage devices 21 are distributed at arbitrary intervals relative to the power supply system, similar to the energy storage device 20 described in the first embodiment, and are each connected to the power supply line 8 and the return line 9. Each energy storage device 21 comprises a battery 1, a power converter 2, a control unit 31, and a voltage detection unit 10. The battery 1 and power converter 2 are the same as the battery 1 and power converter 2 of the energy storage device 20 described in the first embodiment, so their description is omitted.

[0053] The voltage detection unit 10 detects the voltage of the AC system 11 and passes the detected voltage to the control unit 31. The control unit 31 measures the frequency of the AC system 11 based on the voltage detected by the voltage detection unit 10. The control unit 31 generates a power command value for charging and discharging according to the difference between the measured frequency and the reference system frequency (also called the "reference frequency") as a target value, and outputs the power command value to the power converter 2.

[0054] When the balance between power supply and demand is disrupted, frequency fluctuations occur, making the power supply unstable. The control unit 31 controls the frequency F of the AC system 11. 11 and reference system frequency F r The difference ΔF (ΔF=F) from (50Hz or 60Hz) 11 -F rThe system responds to load fluctuations by calculating the difference ΔF and generating a command value according to the difference ΔF. For example, the control unit 31 can generate a command value that minimizes the difference ΔF. The reference system frequency is an example of a target value related to power transfer between the feeder line 8 and the distributed energy storage system 200. Each control unit 3 obtains the reference system frequency in advance and sets it as a target value. A known method may be used to calculate the frequency based on the AC voltage.

[0055] Figure 8 shows an example of power command value generation in a distributed energy storage device system 200 according to the second embodiment. The voltage detection unit 10 detects the voltage of the AC system 11 and passes it to the frequency detection unit 35. The frequency detection unit 35 is provided as a function of the control unit 31. The control unit 31 receives the frequency F detected by the frequency detection unit 35. 11 and reference system frequency F r A power command value is generated according to the difference ΔF. Instead of the difference ΔF, the frequency deviation (ΔF / F) is used. r A power command value corresponding to the difference ΔF may be used. The control unit 31 can generate a power command value using, for example, a table that specifies the correspondence between the difference ΔF and the power command value. An example of such a table is the power command table 61 shown in Figure 8. In Figure 8, the power command table 61 indicates a discharge power command value (positive) whose value increases linearly according to the absolute value of the difference ΔF when ΔF is less than a predetermined first value ΔFa, a power command value of zero when ΔF is greater than or equal to the first value ΔFa and less than the second value ΔFb, and a charge power command value (negative) whose value increases linearly according to the absolute value of the difference ΔF when ΔF is greater than or equal to the second value ΔFb. The power command table 61 is just an example, and other tables may be used. The control unit 31 may calculate the command value using, for example, a relational expression that outputs a power command value corresponding to the difference ΔF or the frequency deviation.

[0056] Thus, in the distributed energy storage device system 200 according to the second embodiment, each distributed energy storage device 21 performs self-control to suppress frequency fluctuations, thereby enabling the entire distributed energy storage device system 200 to adjust the supply and demand of power.

[0057] The self-control system according to the second embodiment may also use commands from a higher-level control device 6. Figure 9 is a schematic diagram showing a second configuration example of the distributed energy storage device system according to the second embodiment. In the second configuration example, the distributed energy storage device system 210 is also used together with a DC power supply system. The DC power supply system comprises an AC power system 11, a substation 4, a power supply line 8, an electric vehicle 5, and a return line 9. The power supply system is the same as in the first configuration example, so its description is omitted. The distributed energy storage device system 210 according to the second configuration example comprises a plurality of energy storage devices 22 distributed with respect to the power supply system, and a higher-level control device 6.

[0058] Each energy storage device 22 comprises a battery 1, a power converter 2, a control unit 32, and a voltage detection unit 10. The battery 1, power converter 2, and voltage detection unit 10 are the same as those in the first configuration example, so a detailed explanation is omitted. Since the higher-level control device 6 is the same as the higher-level control device 6 of the distributed energy storage device system 100 according to the first embodiment, a detailed explanation will be omitted.

[0059] Similar to the first configuration example, the control unit 32 measures the frequency of the AC system 11 based on the voltage of the AC system 11 detected by the voltage detection unit 10, generates a power command value for charging and discharging according to the difference ΔF from the reference system frequency, and outputs it to the power converter 2. Furthermore, similar to each control unit 3 of the energy storage device 20 according to the first embodiment, the control unit 32 communicates bidirectionally with the higher-level control device 6 via the transmission line 7, receives commands from the higher-level control device 6, and transmits feedback to the higher-level control device 6, including, for example, the SOC of the battery 1. Since the control unit 3 and the higher-level control device 6 generally have different response times, this compatibility is possible. In addition, the higher-level control device 6 may also monitor the voltage of the AC system 11.

[0060] (2-2) Effects When high-speed response is required for power supply and demand adjustment, each control unit 3 may not be able to respond in time if it waits for a command from the higher-level control unit 6. As explained in the first configuration example, in the distributed energy storage device system 200 according to the second embodiment, each control unit 3 of the multiple distributed energy storage devices 21 can directly monitor the voltage at the end of the AC grid 11 and perform high-speed control to suppress its frequency fluctuations. As a result, stable supply and demand adjustment can be performed for the entire system.

[0061] Furthermore, as described in the second configuration example, in the distributed energy storage system 210, each distributed energy storage device 22 can be configured to directly monitor the terminal voltage and adjust supply and demand while simultaneously responding to commands from the higher-level control device 6.

[0062] The self-control described in the second embodiment is, in principle, performed by offline control. The self-control shown in the first configuration example of the second embodiment corresponds to the primary adjustment force in the supply and demand adjustment market. In contrast, the control equipped with the higher-level control device 6 is performed by online control and corresponds to the secondary or tertiary adjustment force in the supply and demand adjustment market. When self-control and higher-level control are used in combination, as in the second configuration example of the second embodiment, online control is performed at time intervals of 5 to 15 minutes, and offline control (self-control) is performed at time intervals of 10 seconds. In the second configuration example, a two-stage control can be realized in which the higher-level control device 6 performs low-frequency, low-precision control, and in addition, the control unit 32 of each energy storage device performs high-frequency, precise control.

[0063] (2-3) Variations As an alternative, a higher-level control unit may integrate and control the distributed energy storage system to monitor the voltage of the AC system and suppress frequency fluctuations. Figure 10 is a schematic diagram showing a modified example of the distributed energy storage system according to the second embodiment. The distributed energy storage system 220 according to the modified example is also used together with a DC power supply system, similar to the first and second configurations. The power supply system comprises an AC system 11, a substation 4, a power supply line 8, an electric vehicle 5, and a return line 9. The power supply system is the same as in the first configuration, so its description is omitted. The distributed energy storage system 220 comprises a plurality of energy storage devices 20 distributed with respect to the power supply system, the control device 6, and a voltage detection device 40.

[0064] Each energy storage device 20 comprises a battery 1, a power converter 2, and a control unit 3. The battery 1, power converter 2, and control unit 3 are the same as those of the energy storage device 20 described in the first embodiment, so a detailed explanation is omitted.

[0065] The voltage detection device 40 detects the voltage of the AC system 11 and passes the detected voltage to the higher-level control device 6. The higher-level control device 6 measures the frequency of the AC system 11 based on the voltage detected by the voltage detection device 40. The higher-level control device 6 then calculates a power command value using a table similar to the table 61 exemplified in Figure 8, based on the difference or frequency deviation between the frequency of the AC system 11 and the reference system frequency, and transmits the power command value to the control unit 3 of each energy storage device 20. Each control unit 3 sets a target value based on the received power command value and outputs a command to the power converter 2. In this way, even when the higher-level control device 6 monitors the system voltage, the same integrated control can be performed in the distributed energy storage device system 220.

[0066] (Third embodiment) (3-1) Configuration examples and operation examples The distributed energy storage system according to the third embodiment has the same configuration as the distributed energy storage system 100 according to the first embodiment, except that it is used in conjunction with an AC power supply system. The differences from the first embodiment will be mainly described below.

[0067] Figure 11 is a schematic diagram showing one example configuration of a distributed energy storage system according to the third embodiment. The distributed energy storage system 300 according to the third embodiment is used in conjunction with an AC power supply system. The AC power supply system comprises a first AC system 11, a second AC system 12, a substation 41, a substation 42, a section 50, a feeder line 8, an electric vehicle 5, and a return line 9. The feeder line 8, electric vehicle 5, and return line 9 are the same as the feeder line 8, electric vehicle 5, and return line 9 of the DC power supply system described in relation to the first embodiment, so their description is omitted. The distributed energy storage system 300 comprises a plurality of energy storage devices 20 distributed with respect to the AC power supply system, and a higher-level control device 6.

[0068] The first AC power system 11 and the second AC power system 12 are, for example, commercial power systems with a phase difference between them. The first AC power system 11 and the second AC power system 12 may also be power systems with different frequencies.

[0069] Substation 41 is an AC substation equipped with circuit breakers and transformers that converts three-phase AC power received from the first AC system 11 into single-phase AC power and outputs single-phase AC power to the feeder circuit. Substation 42 is an AC substation equipped with circuit breakers and transformers that converts three-phase AC power received from the second AC system 12 into single-phase AC power and outputs single-phase AC power to the feeder circuit.

[0070] Section 50 is a so-called dead section, positioned to electrically isolate the overhead lines to prevent short circuits of power from different electrification systems, different phases, or different frequencies. Between substation 41, which is supplied with power from the first AC system 11, and substation 42, which is supplied with power from the second AC system 12, the feeder line 8 is isolated by section 50.

[0071] Multiple energy storage devices 20 are distributed at arbitrary intervals and each is connected to a feeder line 8 and a return line 9. Each energy storage device 20 comprises a battery 1, a power converter 2, and a control unit 3. The energy storage device 20 according to the third embodiment is the same as the energy storage device 20 described in the first embodiment, so a detailed description is omitted. However, since the feeder line 8 employs an AC power supply system, the power converter 2 converts the DC from the battery 1 to AC and supplies power to the feeder line 8.

[0072] Since substations 41 and 42 are AC substations, when regeneration occurs, reverse power flow from substation 41 to the three-phase AC system 11, or from substation 42 to the three-phase AC system 12 may occur. For example, each energy storage device 20 can monitor the reverse power flow current from the nearby (same section) substation 41 to the three-phase AC system 11 (shown by arrow R as an example) via the control unit 3, and if reverse power flow occurs, it can operate to charge the battery 1 to absorb the active power. The power converter 2, under the control of the control unit 3, converts the AC received from the feeder line 8 to DC and charges the battery 1. In the third embodiment, the target value related to power exchange between the feeder line 8 and the distributed energy storage device system 300 is, for example, a current threshold for determining the occurrence of reverse power flow.

[0073] (3-2) Effects In the case of an AC power supply system, since the overhead lines are separated into sections, the substation 4 cannot supply power to electric vehicles 5 in adjacent sections that are separated by sections. According to the distributed energy storage device system 300 of the third embodiment, the charging and discharging of the storage battery 1 of the energy storage device 20 can be integrated and controlled across sections separated by sections, and power supply and demand can be adjusted as a whole system.

[0074] (3-3) Variant Figure 12 shows a modified example of the energy storage device 20 in the distributed energy storage device system 300 according to the third embodiment. In Figure 12, the energy storage device 23 is installed across section 50. The energy storage device 23 includes power converters 25 and 26 instead of the power converter 2 shown in Figure 11. Power converter 25 is connected, for example, to the M-side (Main phase) and includes a DC / DC converter and a DC / AC converter. Power converter 26 is connected, for example, to the T-side (Teaser) and includes a DC / DC converter and a DC / AC converter.

[0075] In this modified example, the control unit 3 monitors the reverse power flow at substations (not shown) on both sides of section 50 and controls the charging and discharging of the battery 1 via power converter 25 or power converter 26. This allows the distributed energy storage system 300 to monitor the power for each direction separated by section 50 and to share the power for each direction between the power supply circuits.

[0076] The distributed energy storage device system 300 according to the third embodiment may include a plurality of distributed energy storage devices 20, a plurality of distributed energy storage devices 23, or a combination of one or more energy storage devices 20 and one or more energy storage devices 23 in a distributed configuration.

[0077] (Fourth Embodiment) The distributed energy storage system according to the fourth embodiment includes another energy storage system (hereinafter referred to as "auxiliary energy storage device") located in the AC grid, and controls the auxiliary energy storage device as well in an integrated manner. The distributed energy storage system according to the fourth embodiment has the same configuration as the distributed energy storage system 100 according to the first embodiment, except that it includes an auxiliary energy storage device. The differences from the first embodiment will be mainly described below.

[0078] (4-1) Configuration examples and operation examples Figure 13 is a schematic diagram showing one example configuration of a distributed energy storage system according to the fourth embodiment. The distributed energy storage system 400 according to the fourth embodiment is used together with a DC power supply system, similar to the first embodiment. The DC power supply system comprises an AC system 11, a substation 4, a feeder line 8, an electric vehicle 5, and a return line 9. These are the same as the AC system 11, substation 4, feeder line 8, electric vehicle 5, and return line 9 of the DC power supply system described in relation to the first embodiment, so their description is omitted.

[0079] The distributed energy storage system 400 comprises a plurality of energy storage devices 20 distributed with respect to the power supply system, a higher-level control device 6, and an auxiliary energy storage device 24.

[0080] The multiple energy storage devices 20 are distributed at arbitrary intervals relative to the power supply system, similar to the energy storage device 20 described in the first embodiment, and are each connected to the power supply line 8 and the return line 9. Each energy storage device 20 comprises a battery 1, a power converter 2, and a control unit 3. Since these batteries 1, power converter 2, and control unit 3 are the same as those of the energy storage device 20 described in the first embodiment, a detailed explanation is omitted.

[0081] The auxiliary energy storage device 24 is connected to the third AC power grid 13. The auxiliary energy storage device 24 is, for example, an energy storage device that can be charged and discharged in and out of the commercial power supply of the station building. The AC power grid 11 and the third AC power grid 13 do not need to be distinguished and may originate from the same power company's commercial power grid.

[0082] The auxiliary energy storage device 24, like the distributed energy storage devices 20, comprises a battery 1, a power converter 2, and a control unit 3. These battery 1, power converter 2, and control unit 3 have the same configuration and function as the battery 1, power converter 2, and control unit 3 of the energy storage device 20. The output of the auxiliary energy storage device 24 is connected to the feeder line 8 via a transformer (not shown). The control unit 3 of the auxiliary energy storage device 24 also communicates bidirectionally with the higher-level control unit 6 via a transmission line 7.

[0083] The higher-level control device 6 monitors the charging and discharging status of the energy storage devices 20 distributed within the power supply system and utilizes the output of the auxiliary energy storage device 24 when there is a power shortage. For example, if the sum of the discharge power values ​​received from the multiple energy storage devices 20 under monitoring is less than the discharge power value required in the supply and demand plan, the higher-level control device 6 can determine that there is a power shortage and instruct the control unit 3 of the auxiliary energy storage device 24 to discharge the battery 1. Alternatively, for example, if the sum of the power command values ​​actually output by the multiple energy storage devices 20 under monitoring is less than the sum of the power command values ​​output from the higher-level control device 6 to each control unit 3, the higher-level control device 6 can determine that there is a power shortage and instruct the control unit 3 of the auxiliary energy storage device 24 to discharge the battery 1. In the fourth embodiment, an example of a target value related to power exchange between the power supply line 8 and the distributed energy storage device system 400 is a threshold used to determine a power shortage, such as the sum of the discharge power value or power command value required in the supply and demand plan.

[0084] (4-2) Effects Generally, the charging and discharging power of the energy storage devices 20 distributed within the power supply system depends on and is limited by the load of the electric vehicles 5 running within the power supply system. If there is not enough load in the power supply circuit, the energy storage devices 20 cannot discharge properly and cannot perform the necessary supply and demand adjustments. For example, in the event of a personal injury accident or a natural disaster such as an earthquake, force majeure such as a failure of the power supply equipment may reduce the charging and discharging capacity of each energy storage device 20 that is responsible for supply and demand adjustment in the distributed energy storage device system 400. In such cases, the distributed energy storage device system 400 can supply the insufficient charging and discharging power from the auxiliary energy storage device 24. The higher-level control device 6 monitors the charging and discharging status of each energy storage device 20 via the transmission line 7, and if each energy storage device 20 is unable to follow the desired command, it is possible to supplement the supply and demand adjustment capacity by charging and discharging the auxiliary energy storage device 24, enabling planned supply and demand adjustments for the entire system.

[0085] As described in detail above, according to the distributed energy storage device system of the embodiment, each of the multiple energy storage devices distributed within the power supply system includes a power converter connected to the power supply line, a battery connected to the power converter and capable of charging and discharging with the power supply line via the power converter, and a control unit that sets a target value for power exchange between the power supply line and the distributed energy storage device system, generates a command value for charging and discharging the battery based on the target value, and outputs the command value to the power converter. This makes it possible for each energy storage device to charge and discharge more systematically, rather than simply charging and discharging in response to the rise / fall in voltage of the power supply line or overhead line, and enables the system as a whole to perform the necessary power supply and demand adjustments.

[0086] Therefore, the distributed energy storage system according to this embodiment can perform planned power supply and demand adjustment as a whole system by controlling the charging and discharging of batteries in each energy storage device distributed within the power supply system.

[0087] However, this invention is not limited to the embodiments described above. For example, in the distributed energy storage device system according to each embodiment, each distributed energy storage device may or may not be a unitized device. Energy storage device may be read as energy storage system. As an example, if an electric vehicle 5 is equipped with an energy storage device or energy storage system, that energy storage device, etc., may also be incorporated into the distributed energy storage device system. The higher-level control device 6 can transmit commands to the energy storage device, etc., of the electric vehicle 5 by wire or wireless connection, causing it to perform charging and discharging for power supply and demand adjustment. Similarly, different types of energy storage or energy storage systems may be incorporated into the distributed energy storage device system according to the embodiment.

[0088] In the distributed battery arrangement system according to each embodiment, the multiple distributed energy storage devices may all have the same configuration or may have different configurations. For example, an energy storage device equipped with a battery 1 and an energy storage device equipped with an electric double-layer capacitor instead of a battery 1 may be mixed together in the distributed energy storage device arrangement system. Furthermore, in the distributed energy storage device arrangement system according to each embodiment, the higher-level control device 6 may be realized by the coordinated operation of multiple higher-level control devices.

[0089] 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. (Note 1) A distributed energy storage system comprising multiple energy storage devices arranged in a distributed manner, Each of the aforementioned multiple energy storage devices A power converter connected to the feeder line, A storage battery connected to the power converter and capable of charging and discharging with the feeder line via the power converter, A control unit sets a target value for power transfer between the feeder line and the distributed energy storage device system, generates a command value for charging and discharging the battery based on the target value, and outputs the command value to the power converter. A distributed energy storage system equipped with the following features. (Note 2) The aforementioned target value is, A first voltage value representing the target voltage at which the voltage of the feeder line should be maintained, or A second voltage value representing the target voltage of the feeder line at which charging of the battery should begin, A third voltage value representing the target voltage of the feeder line at which discharge from the battery should begin, The power value representing the target charge / discharge power of the aforementioned battery, A first current value representing a current limit value that limits the charging current to the aforementioned battery, or A second current value representing a current limit value that limits the discharge current from the aforementioned battery. A distributed energy storage device system as described in Appendix 1, comprising at least one of the following: (Note 3) A higher-level control device that provides overall control of the aforementioned multiple energy storage devices, Based on a supply and demand plan set between the power supply system including the energy storage device and the commercial power grid, first control information regarding the charging and discharging of the distributed energy storage device system is received. A higher-level control device generates and transmits second control information regarding the charging and discharging of the energy storage device to at least one of the plurality of energy storage devices based on the first control information. A distributed energy storage device system as described in Appendix 1 or Appendix 2, further comprising the above. (Note 4) The energy storage device is a distributed energy storage device system according to any one of the appendices 1 to 3, characterized in that the energy storage device is equipped with charge / discharge control that equalizes the charge rate among the distributed energy storage devices. (Appendix 5) The distributed energy storage system according to Appendix 3, wherein the first control information or the second control information includes an instruction to change the discharge characteristics or charging characteristics with respect to the charge rate in at least one of the plurality of energy storage devices. (Note 6) The distributed energy storage system according to any one of Appendix 1 to Appendix 5, characterized in that the plurality of energy storage devices have at least one of the following characteristics: an output voltage characteristic in which the output voltage to the power line decreases when the feeder line output current increases in order to equalize the load on the energy storage devices, or a characteristic in which the output voltage decreases in accordance with the decrease in the charge level of the storage battery. (Note 7) The distributed energy storage system according to Appendix 3, wherein at least one of the plurality of energy storage devices is monitored by the control unit for the power values ​​charged and discharged between the battery and the feeder line, and the monitored power values ​​are transmitted to the higher-level control unit. (Note 8) The distributed energy storage system according to Appendix 7, wherein the higher-level control device calculates the difference between the power values ​​charged and discharged between the battery and the feeder line received from the energy storage device and the supply and demand plan, and generates the second control information based on the calculated difference. (Note 9) Each of the aforementioned plurality of energy storage devices further comprises a detection unit for detecting the voltage received from the commercial power grid to the feeder line, At least one of the plurality of energy storage devices measures the frequency of the commercial power grid based on the detected power receiving voltage, generates a command value such that the difference between the measured frequency and the reference frequency is less than or equal to a predetermined value, and outputs it to the power converter. A distributed energy storage device system as described in any of Appendix 1 to Appendix 8. (Note 10) The higher-level control device detects the power receiving voltage from the commercial power system to the feeder line, measures the frequency of the commercial power system based on the detected power receiving voltage, and generates the second control information such that the difference between the measured frequency and the reference frequency is less than or equal to a predetermined value. The distributed energy storage device system described in Appendix 3. (Note 11) The distributed energy storage system includes a power converter that converts alternating current to direct current connected to the feeder line, an auxiliary energy storage device equipped with a battery on the AC side of the power system of the power converter, and the higher-level control device outputs a command regarding charging and discharging to the auxiliary energy storage device when the sum of the power values ​​charged and discharged between the battery and the feeder line received from each of the plurality of energy storage devices falls below the value required in the supply and demand plan. The distributed energy storage device system described in Appendix 3. [Explanation of Symbols]

[0090] 1...Battery, 2, 25, 26...Power converter, 3, 31, 32...Control unit, 4, 41, 42...Substation, 5...Electric vehicle, 6...Higher-level control unit, 7...Transmission line, 8...Feeder line, 9...Return line, 10...Voltage detection unit, 11, 12, 13...AC system, 20, 21, 22, 23...Energy storage device, 24...Auxiliary energy storage device, 35...Frequency detection unit, 40...Voltage detection device, 50...Section, 61...Power command table, 100, 110, 200, 210, 220, 300, 400...Energy storage device distributed arrangement system.

Claims

1. Multiple energy storage devices connected to a feeder line, A higher-level control device that centrally controls the aforementioned multiple energy storage devices, A distributed energy storage device system comprising: The aforementioned higher-level control device is Based on the power supply and demand plan, first control information regarding the supply of power to the power lines is received, Based on the first control information, For at least one of the aforementioned plurality of energy storage devices, The system generates and transmits second control information regarding the charging and discharging of the energy storage device. The aforementioned multiple energy storage devices are, Based on the second control information, control related to charging and discharging is performed. A distributed energy storage system.

2. The second control information is generated according to the state of the energy storage device. A distributed energy storage device system according to claim 1.

3. The state of the energy storage device includes the charge level of the energy storage device. The distributed energy storage device system according to claim 2.

4. The second control information includes an instruction to change the charging characteristics or discharging characteristics of the energy storage device, A distributed energy storage device system according to claim 1.

5. The second control information is generated based on the state of the plurality of energy storage devices. A distributed energy storage device system according to claim 1.

6. The higher-level control device receives the charge and discharge information from the energy storage device. A distributed energy storage device system according to claim 1.

7. The second control information is Based on the difference between the charge / discharge amount in the energy storage device and the supply and demand plan, The distributed energy storage device system according to claim 6.

8. The plurality of energy storage devices are controlled so as to equalize the charge levels. A distributed energy storage device system according to claim 1.

9. The second control information is generated based on the state of the feeder line or commercial power system, A distributed energy storage device system according to claim 1.

10. The higher-level control device outputs control information regarding charging and discharging to other energy storage devices when the power supply from the plurality of energy storage devices is insufficient. A distributed energy storage device system according to claim 1.

11. A control device for centrally controlling a plurality of energy storage devices connected to a feeder line, Based on the power supply and demand plan, first control information regarding the power supply to the feeder line is received, Based on the first control information, second control information relating to the charging and discharging of the energy storage device is generated and output to at least one of the plurality of energy storage devices. Control device.

12. A power storage device connected to a feeder line, Based on the power supply and demand plan, the system receives second control information regarding the charging and discharging of the energy storage device, which is generated by a higher-level control device based on first control information regarding the supply of power to the feeder line. Based on the second control information, control related to charging and discharging is performed. Energy storage device.

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