Power supply system, power supply control device control method and program

Abstract

To provide a technique capable of saving labor relating to setting of a power supply controller while stabilizing output control as a whole power supply system, according to the system comprising a plurality of power supplies and power supply controllers.SOLUTION: A power supply system according to the invention interconnects with a commercial power supply system and comprises a plurality of power supply facilities each comprising a power supply and a power supply controller. Each power supply controller comprises an own device operational situation transmission unit for transmitting information about an operational situation of an own device; an another-device-operational-situation reception unit for receiving information about an operational situation of another power supply controller; and an output control unit for determining a predetermined numerical value relating to output control of power from the power supply, using the information about the operational situation of the other power supply controller.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a power system, a control method for a power control device, and a program.

Background Art

[0002] Conventionally, a distributed power system including a power supply source for a load and a power conversion device (power conditioner) connected thereto is known. However, when connecting such a distributed power system to a commercial power system, reverse power flow may not be allowed. In such a case, the power at the power receiving point in the connection path between the distributed power system and the commercial power system is detected, and the output power of the distributed power source is adjusted to suppress the reverse power flow of the output power to the system side (for example, Patent Document 1, etc.).

[0003] By the way, as a form of the above power system, there is a system composed of a plurality of power conditioners. In such a case, it is necessary to control the output of each power conditioner so that the sum of the outputs of the plurality of power conditioners does not exceed the load (that is, does not cause reverse power flow). However, if each power conditioner performs output control individually, there is a problem that the control of the entire power system becomes unstable. That is, the control constant (control gain) related to the calculation of the control amount for a predetermined control target determined so as not to cause reverse power flow in relation to the load is multiplied by the number of power conditioners as seen in the entire power system. Therefore, as the number of power conditioners in the system increases, the overall output becomes less stable (the overshoot and undershoot with respect to the control target are repeated indefinitely). For this reason, it was necessary to limit the number of power storage facilities in the system to a small number or manually adjust the control gain of each power conditioner individually so that the overall output of the system does not cause reverse power flow.

[0004] In contrast, in a distributed power system using solar power generation as a power source, for example, it has been proposed to designate one of the multiple power conditioners as a master unit to monitor reverse power flow, and to use the information detected by the master unit (output power amount, fault information, operating status, etc.) to control the output of the other power conditioners (slave units) (for example, Patent Documents 2 to 5). According to this, the control of the master unit and each slave unit can be performed so that the output of the entire system becomes a predetermined control target, optimizing the output control of each power conditioner and enabling stable output control of the entire system. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2002-238166 [Patent Document 2] Japanese Patent Publication No. 2021-093816 [Patent Document 3] Japanese Patent Publication No. 2021-093817 [Patent Document 4] Japanese Patent Publication No. 2021-093818 [Patent Document 5] Japanese Patent Publication No. 2021-097530 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, as described in the above-mentioned patent document, when a power conditioner related to solar power generation is used as the master unit, there is a problem that it cannot perform its function at night. Furthermore, in the first place, one of the multiple power conditioners must be set as the master unit, which creates the problem of the effort required to set the master unit.

[0007] The present invention has been made in view of the above circumstances, and its purpose is to provide a technology that can stabilize the control of the output of a power supply system as a whole, and reduce the labor involved in setting up the power supply control device, in a power supply system equipped with multiple power sources and power supply control devices. [Means for solving the problem]

[0008] One form of disclosure technology to solve the above problems is, A power supply system comprising multiple power supply facilities that are connected to a commercial power grid and equipped with a power supply and a power control device that controls at least the power output from the power supply, and capable of supplying AC power to a load, The power control devices of each of the aforementioned power supply facilities have a communication path that enables them to communicate with each other. Each of the aforementioned power control devices is: A device operating status transmission unit that transmits information relating to the operating status of the device via the aforementioned communication path, A receiving unit for the operating status of other devices receives information relating to the operating status of other power control devices via the aforementioned communication path. An output control unit that uses information relating to the operating status of the aforementioned other power control devices to determine a predetermined numerical value related to power output control from the power supply that is the control target of its own device, This power supply system is characterized by having the following features:

[0009] Here, "power control device" can be understood as a so-called power conditioner (PCS: Power Conditioning System), or a part thereof. Furthermore, "information related to operating status" may include, for example, information on whether each power control device is operating, and if operating, the device's unique unit number. Also, "communication path" includes not only wired but also wireless connections.

[0010] With this configuration, each power control unit can control the power output of the power supply to which it is connected, taking into account the operating status of other power control units in the system. In other words, if the power control units are PCS (Power Conditioning Systems), each PCS can control the output of AC power from its own unit so that the entire system is optimized without the need for a master unit.

[0011] Furthermore, the power supply system has measuring means for measuring at least the physical quantity related to power at the measurement point between the commercial power grid and the load. The output control unit may perform power output control by feedback (FB) control, which uses a power control target value at the measurement point that is set in advance to prevent reverse power flow to the commercial power grid, and a state quantity calculated based on the physical quantity obtained from the measurement means.

[0012] Here, the "measuring means" can be, for example, an ammeter or a voltmeter. The measuring means may also detect the direction of the current in addition to the current value at the measurement point. Furthermore, the "control target value" as used here does not refer only to a single value, but also includes a numerical range with a width defined by upper and lower limits. In addition, the "state quantity" above can be the effective values ​​of current and voltage when measured by the measuring means, or it can be the power value calculated using these values.

[0013] With this configuration, each power control device can perform feedback control with respect to the control target value of the entire power system (for example, the power value at the measurement point) based on the measured value obtained from the measurement means. And in this feedback control, the system Since information regarding the operating status of other power control devices within the system can be used, the output control of each power control device can be optimized relative to the control target value of the entire power system.

[0014] Furthermore, the predetermined numerical value is a control constant related to the feedback control, The output control unit may determine the control constant based on its ratio to a predetermined index that applies to the entire power control device operating within the power system.

[0015] Here, "control constant" refers to, for example, the proportionality constant in the case of proportional control, and is also called the control gain. With this configuration, a predetermined index relating to the entire operating system can be used as the base number, and the control constant can be determined based on the ratio (ratio to the total number) of that index in the individual device. As a result, even if there is an increase or decrease in the number of operating power control devices in the system, such as when there is a power control device that is not operating (due to failure, etc.) or when a new power control device is installed, each power control device can perform output control optimized for the control target of the entire power system.

[0016] The predetermined index may also be the number of power control devices. In this case, the "ratio of the device itself" is the value obtained by dividing the total number of power control devices operating in the power system by 1. Alternatively, the power control device may be a power conditioner, and the predetermined index may be the rated capacity of the power conditioner's output power. In this case, the "ratio of the device itself" is the value obtained by dividing the rated capacity of the device itself by the sum of the rated capacities of the power conditioners operating in the power system. The control constant for feedback control in each power control device may be determined by multiplying the "ratio of the device itself" calculated in this way by a given control constant for the entire system.

[0017] Furthermore, the power supply system may include a storage battery as the power source. In particular, in the case of a power supply system that is equipped only with a storage battery (i.e., without power generation equipment), the present invention is preferable because it can optimize the output control of the entire system (i.e., it can improve the ability to follow the control target value) from the viewpoint of preventing reverse power flow to the commercial power grid.

[0018] Further, the present invention can also be understood as follows. That is, In a power supply system including a plurality of power supply facilities capable of supplying AC power to a load, which are connected to a commercial power system and include a power supply control device that controls at least the power output from the power supply, a control method for each power supply control device, An other device information acquisition step of acquiring information related to the operating status of other power supply control devices included in the power supply system; A self device information output step of outputting information related to the operating status of the self device; A control parameter setting step of determining a predetermined numerical value related to the power output control from the power supply that is the control target of the self device by using the information related to the operating status of the other power supply control devices; A control method for a power supply control device, characterized by comprising the above.

[0019] Further, the predetermined numerical value is a control constant related to feedback control using a preset control target value and a state quantity, and in the control parameter setting step, the control constant may be determined based on the ratio of the self device in a predetermined index for the entire power supply control devices operating in the power supply system. Further, the predetermined index may be the number of power supply control devices, or when the power supply control device is a power conditioner, it may be the rated capacity related to the output power of the power conditioner.

[0020] Further, the present invention can also be understood as a program for causing a control device of a storage battery to execute the above method, and a computer-readable recording medium in which such a program is non-temporarily recorded.

Effects of the Invention

[0021] According to the present invention, in a power supply system including a plurality of power sources and power supply control devices, it is possible to provide a technology capable of stabilizing the control of the power output of the entire system and achieving labor saving related to the setting of the power supply control device.

Brief Description of the Drawings

[0022] [Figure 1] Figure 1 is a block diagram showing a schematic configuration of a power supply system according to an embodiment of the present invention. [Figure 2] Figure 2A is a block diagram showing the schematic configuration of an energy storage system according to an embodiment of the present invention. Figure 2B is a block diagram showing a functional module of an energy storage PCS according to an embodiment of the present invention. [Figure 3] Figure 3 is an explanatory diagram illustrating the challenges of the conventional technology. [Figure 4] Figure 4 shows an example of the hardware configuration of the control unit of an energy storage PCS according to an embodiment of the present invention. [Figure 5] Figure 5 is a flowchart showing an example of the control processing flow performed in a power storage PCS according to an embodiment of the present invention. [Figure 6] Figure 6 is a flowchart showing subroutines in the control processing performed in an embodiment of the present invention of the energy storage PCS. [Figure 7] Figure 7 is a time chart illustrating the processing when the number of operating energy storage PCS increases in a power supply system according to an embodiment of the present invention. [Figure 8] Figure 8 is a time chart illustrating the processing that occurs when the number of operating energy storage PCS decreases in a power supply system according to an embodiment of the present invention. [Modes for carrying out the invention]

[0023] <Examples of application> The following describes examples of applications of the present invention with reference to the drawings. The present invention can be applied, for example, to a self-consumption type power supply system 1 as shown in Figure 1, and to a power storage PCS 20 used therein. Figure 1 is a block diagram showing the schematic configuration of a power supply system 1 to which the present invention is applied. As shown in Figure 1, the power supply system 1 according to this application example is connected to a commercial power grid 80 and consists of a plurality of power storage facilities 2a, 2b, 2c, communication lines 31 connecting each power storage facility 2a, 2b, 2c (more specifically, the power storage PCS 20a, 20b, 20c described later), a load 50, a power meter 82, and communication lines 32 connecting the power meter 82 and the power storage facilities 2a, 2b, 2c (more specifically, the power storage PCS 20a, 20b, 20c described later). In the figure, solid lines connecting each block indicate power lines (power paths), and dashed lines indicate communication lines.

[0024] Furthermore, as shown in Figure 1, the energy storage equipment 2a is equipped with a battery unit 27a and a power conditioning system (PCS) 20a. The same applies to energy storage equipment 2b and 2c. In the following, when it is necessary to distinguish between energy storage equipment, battery units, and power conditioning systems, they will be described as energy storage equipment 2a, energy storage equipment 2b, energy storage equipment 2c, battery unit 27a, battery unit 27b, battery unit 27c, power conditioning PCS 20a, power conditioning PCS 20b, and power conditioning PCS 20c, respectively. However, when it is not necessary to distinguish between them, they will simply be described as "energy storage equipment 2," "battery unit 27," and "power conditioning PCS 20." Note that energy storage equipment 2, battery unit 27, and power conditioning PCS 20 in this application example are examples of "power supply equipment," "power supply," and "power supply control device" according to the present invention.

[0025] The energy storage PCS20 in this application example is a so-called power conditioner, functioning as a power conversion device that converts DC power to AC power and outputs it. Hereafter, DC will also be referred to as DC (Direct Current) and AC as AC (Alternating Current). Figure 2A is a block diagram illustrating the general hardware configuration of the energy storage PCS20 in this application example. As shown in Figure 2A, the energy storage PCS20 includes a control unit 21, a bidirectional DC / DC converter 22, and a bidirectional DC / AC inverter 23.

[0026] The control unit 21 of the energy storage PCS 20 is a computer that has a storage medium for storing control programs and a processor such as a CPU that executes control procedures according to the control programs. The control unit 21 controls each component of the energy storage PCS 20 based on various information obtained from the outside via various sensors (not shown) and communication lines 31 and 32 within the energy storage PCS 20.

[0027] Furthermore, as shown in Figure 2B, the energy storage PCS 20 includes functional modules for a self-device information transmission unit 211, a non-device information reception unit 212, and a charge / discharge power control unit 213. These functional modules are realized by a program executed by the control unit 21 and the hardware configuration of the energy storage PCS 20. In this application example, the self-device information transmission unit 211, the non-device information reception unit 212, and the charge / discharge power control unit 213 are examples of a self-device operating status transmission unit, a non-device operating status reception unit, and an output control unit, respectively, according to the present invention.

[0028] In power supply systems with multiple energy storage facilities as described above, conventional technology prevents reverse power flow by having each energy storage PCS determine its output power through feedback (FB) control based on control parameters such as a control target (power value), the power value at a grid power measurement point (hereinafter simply referred to as a measurement point), and pre-set control constants. However, in such cases, when viewed as a whole system, the control gain related to FB control is multiplied by the number of energy storage PCS units, so the overall output becomes less stable as the number of energy storage PCS units in the system increases.

[0029] Figure 3 shows an explanatory diagram illustrating the relationship between the number of energy storage PCS units operating in the system and the fluctuation of power values ​​at the measurement points. The explanatory diagram in Figure 3 is a graph with power values ​​at the measurement points on the vertical axis and elapsed time on the horizontal axis. In the figure, the solid line schematically shows the fluctuation of power values ​​when there is one energy storage PCS unit in operation, the dashed line shows the fluctuation of power values ​​when there are five energy storage PCS units in operation, and the dotted line shows the fluctuation of power values ​​when there are ten energy storage PCS units in operation. Before the (rapid) load fluctuation shown in the figure occurs, a stable output is provided relative to the control target value in all cases of one, five, or ten units. However, after the load fluctuation, the fluctuation relative to the control target value becomes larger as the number of energy storage PCS units increases. To avoid this, measures such as limiting the number of energy storage facilities in the system and / or manually adjusting the control gain related to the output control of each energy storage PCS unit were necessary.

[0030] In this regard, the power supply system 1 according to this application example takes the following measures to ensure that even if the number of energy storage PCS 20 in the system increases, the output of the entire system (i.e., the power value at the measurement point) can be stably controlled relative to the control target value for the entire system. Specifically, in the power supply system 1 according to this application example, each energy storage PCS 20 transmits information about its operating status (for example, whether it is running or stopped) to other energy storage PCS 20 via its own device information transmission unit 211, and acquires information about the operating status from other energy storage PCS 20 via its other device information receiving unit 212. Then, based on the operating status of other systems, the charge / discharge power control unit 213 determines the control gain for its own output control. Specifically, predetermined indicators (for example, number of units, rated output) apply to all energy storage PCS operating in the system. The control gain related to the output control of the device is determined by multiplying the ratio of the device itself (etc.) by a preset control gain.

[0031] According to this, stable output control can be achieved for the entire system without limiting the number of energy storage devices in the system. Furthermore, since each energy storage PCS automatically determines its own control gain, it becomes unnecessary to manually readjust the control parameters of each energy storage PCS each time there is an increase or decrease in the number of energy storage devices, thus preventing human error (incorrect setting) when manually setting control parameters. In other words, according to power supply system 1 in this application example, it is possible to stabilize the power output control of the entire system in a power supply system with energy storage devices, and to reduce the labor involved in setting up the power conditioner.

[0032] <Embodiment 1> In the following, specific embodiments of the present invention will be described in more detail with reference to the drawings. Note that the power supply system 1 according to this embodiment is the same as that shown in the application example; therefore, any parts that overlap with the description in the application example above will be omitted.

[0033] (System Configuration) As described above, the power supply system 1 is composed of multiple energy storage PCS 20a, 20b, and 20c, a communication line 31 connecting each of the energy storage PCS 20a, 20b, and 20c, a load 50, a power meter 82, and a communication line 32 connecting the power meter 82 to the energy storage PCS 20a, 20b, and 20c. Each communication line can be configured to support, for example, the CAN (Controller Area Network) communication protocol.

[0034] Each energy storage PCS 20, as shown in Figure 2A, is equipped with a control unit 21, a bidirectional DC / DC converter 22, and a bidirectional DC / AC inverter 23. Furthermore, as shown in Figure 2B, it includes functional modules for transmitting its own device information 211, receiving information from other devices 212, and a charge / discharge power control unit 213. These functional modules are realized through programs executed by the control unit 21 and the hardware configuration of the energy storage PCS 20.

[0035] The self-device information transmission unit 211 transmits information regarding the operating status of its own device to other energy storage PCS 20 via the communication line 31. The other-device information receiving unit 212 receives information regarding the operating status of other energy storage PCS 20 via the communication line 31. The charge / discharge power control unit 213 uses the information regarding the operating status of other energy storage PCS to determine a predetermined value for controlling the output power from the battery, which is the control target of its own device. Specifically, it sets the control gain related to FB control based on the operating status of other devices. The "information regarding the operating status" includes whether or not operation has started (is running) and the unique unit number of the self-device.

[0036] In the energy storage PCS 20, the bidirectional DC / DC converter 22 and the bidirectional DC / AC inverter (power conversion unit) 23 are connected by a predetermined bus (DC bus). The bidirectional DC / DC converter 22 is a unit that bidirectionally converts the voltage of the discharged power discharged from the battery unit 27 and the voltage of the charging power supplied to the battery unit 27 from the bidirectional DC / AC inverter 23. The bidirectional DC / AC inverter 23 is a unit that includes an AC / DC converter that converts AC power supplied from the commercial power grid 80 into DC power and outputs it to a predetermined bus, and a DC / AC inverter that converts the DC power output to the predetermined bus into AC power synchronized with the commercial power grid 80. The battery unit 27 and the bidirectional DC / DC converter 22 incorporate a microcontroller and the like that operate in response to control commands from the control unit 21.

[0037] The control unit 21 includes a processor (CPU, etc.), memory, gate driver, and communication interface. This unit is composed of circuits and the like. The control unit 21 receives input from various sensors, including power meters (ammeters, voltmeters) installed at various locations in the energy storage equipment 2, and information acquired via communication lines 31 and 32. The control unit 21 performs control processing related to charging and discharging based on the status of the load 50 detected through the various sensors, and preset charging and discharging modes.

[0038] For example, when discharging, the control unit 21 converts the power discharged from the battery unit 27 to a voltage via the bidirectional DC / DC converter 22, and then converts the resulting DC power to AC power synchronized with the commercial power grid 80 and outputs it from the bidirectional DC / AC inverter 23. When stopping the discharge, the control unit 21 stops the discharge from the battery unit 27 and stops the AC power output from the bidirectional DC / AC inverter 23 based on the discharged power. Furthermore, if the control unit 21 determines to perform charging based on the above mode, load conditions, State of Charge (SOC) of the battery unit 27, etc., it converts the AC power supplied from the commercial power grid 80 to DC power and controls the battery unit 27 to charge it. The operation of the battery unit 27, the bidirectional DC / DC converter 22, and the bidirectional DC / AC inverter 23 is controlled upon receiving control commands from the control unit 21 regarding the above power storage control process.

[0039] The battery unit 27 is a unit that includes a secondary battery, such as a lithium-ion battery, and is connected to the energy storage PCS 20. The battery unit 27 is also equipped with sensors (not shown) that measure current, voltage, temperature, etc., and the output values ​​of these sensors are transmitted to the control unit 21 of the energy storage PCS 20.

[0040] Load 50 consists of general electrical appliances that consume power, connected to the power storage PCS 20 via a power line, and supplied with power discharged from the battery unit 27. Specifically, this includes various electrical appliances used in homes, such as air conditioners, microwave ovens, and televisions, as well as machinery and lighting equipment such as air conditioners and lighting fixtures used in commercial and industrial facilities.

[0041] The power meter 82 includes an ammeter and a voltmeter and is placed between the load 50 and the commercial power grid 80. The power values ​​measured by the power meter 82 are transmitted to each energy storage PCS 20 via the communication line 32. The current value and its direction may also be transmitted to the energy storage PCS 20. Hereinafter, the locations in the power supply system 1 where the power meter 82 is installed will also be referred to as measurement points.

[0042] (Control unit of the energy storage PCS) Next, the control unit 21 of the energy storage PCS 20 will be described in detail. Figure 4 is a diagram showing an example of the hardware configuration of the control unit 21 of the energy storage PCS 20 according to this embodiment. As shown in Figure 4, the control unit 21 is a computer whose components include a processor 101, main memory 102, auxiliary storage 103, communication IF 104, and input / output IF 105, which are interconnected by a connection bus 106. The main memory 102 and auxiliary storage 103 are recording media that the control unit 21 can read. Multiple instances of each of the above components may be provided, or some components may be omitted. The microcontrollers provided in the battery unit 27 and the bidirectional DC / DC converter 22 are implemented with a hardware configuration substantially equivalent to that of the control unit 21.

[0043] The processor 101 is a central processing unit that controls the entire control unit 21. The processor 101 is, for example, a CPU (Central Processing Unit), an MPU (Micro-Processing Unit), or a DSP (Digital Signal Processor). The processor 101, for example, expands a program stored in the auxiliary storage device 103 into an executable state in the working area of ​​the main memory device 102, and The system provides functions that meet a predetermined purpose by controlling peripheral devices through program execution. However, some or all of the functions provided by the processor 101 may be provided by an ASIC (Application Specific Integrated Circuit), a GPU (Graphics Processing Unit), etc. Similarly, some or all of the functions may be implemented by an FPGA (Field-Programmable Gate Array), a dedicated LSI (large-scale integration) such as a numerical processing processor, or other hardware circuits.

[0044] The main memory 102 and the auxiliary storage device 103 constitute the memory of the control unit 21. The main memory 102 stores programs executed by the processor 101, data processed by the processor, etc. The main memory 102 includes flash memory, RAM (Random Access Memory), and ROM (Read Only Memory). The auxiliary storage device 103 is a storage medium that stores programs executed by the processor 101, etc., and setting information for operation, etc. The auxiliary storage device 103 includes, for example, an HDD (Hard-disk Drive), SSD (Solid State Drive), EPROM (Erasable Programmable ROM), flash memory, USB memory, SD (Secure Digital) memory card, etc. The communication IF 104 is a communication interface with the communication network. The communication IF 104 can adopt an appropriate configuration depending on the connection method with the connected communication network. In this embodiment, various control commands are notified between the bidirectional DC / DC converter 22 and the battery unit 27 connected via the communication IF 104.

[0045] The input / output IF105 is an interface for inputting and outputting data between the input and output devices of the energy storage PCS20. Through the input / output IF105, data is output to display devices such as LCDs and output devices such as printers connected to the energy storage PCS20. Furthermore, operation instructions are received through the input / output IF105, and the processing intended by the operator is performed based on these instructions. In addition, in this embodiment, information communication can be performed with external devices (e.g., other energy storage PCS20s, power meters, etc.) via the input / output IF105 and communication lines 31 and 32. The communication protocol with external devices such as other energy storage PCS20s is not particularly limited, but for example, the CAN communication protocol can be used.

[0046] The energy storage PCS 20, under the control of the control unit 21 as described above, converts the power from the battery unit 27 into AC power synchronized with the commercial power grid 80 and supplies it to the load 50. If the sum of the output power from each of the energy storage PCS 20a, 20b, and 20c is insufficient to meet the power consumption of the load 50, the power supply system 1 receives commercial power from the commercial power grid 80. On the other hand, if the sum of the output power from each of the energy storage PCS 20a, 20b, and 20c is greater than the power consumption of the load 50, there is a risk of reverse power flow to the commercial power grid 80. Therefore, it is necessary to control the output of each of the energy storage PCS 20a, 20b, and 20c so that the sum of the output power does not exceed the threshold at which reverse power flow to the commercial power grid 80 occurs.

[0047] (Control process flow of the energy storage PCS) In this embodiment, the energy storage PCS20 performs such output control by FB control based on control parameters such as a control target value, the power value at the measurement point, and the control gain. Each energy storage PCS20 then automatically determines its own control gain based on information related to the operating status of other energy storage PCS20, thereby optimizing the output control of the power supply system 1 as a whole. The output control process performed in the energy storage PCS20 will be described below with reference to Figure 5.

[0048] Figure 5 is a flowchart showing an example of the processing performed in each energy storage PCS 20. As shown in Figure 5, each energy storage PCS 20 in the power supply system 1 first acquires information regarding the operating status of other energy storage PCS 20. Specifically, the other device information receiving unit 212 The unit numbers of other operational energy storage PCS20s are received (step S101).

[0049] The unit number is a unique number that identifies each device. Therefore, it is not normally possible for multiple energy storage PCS20 units with the same unit number to exist within power supply system 1, and if such a situation occurs, it indicates a malfunction.

[0050] Returning to the explanation of the process in Figure 5, in step S102, the control unit 21 performs a process to determine whether or not there is another energy storage PCS20 having the same unit number as its own device. If the control unit 21 determines that there is another energy storage PCS20 with the same unit number as its own device, the energy storage PCS20 notifies of the occurrence of an abnormality via the output means through the input / output IF105 (S107) and stops operation (S108).

[0051] On the other hand, in step S102, if it is determined that there are no other energy storage PCS20 having the same unit number as the device itself, the device information transmission unit 211 transmits the device's unit number to the other energy storage PCS20 via the communication line 31 (S103). Then, in step S104, the charge / discharge power control unit 213 performs a process to set control parameters for controlling the output of AC power based on the information regarding the operating status of the other device acquired in step S101 (S104).

[0052] In step S104, the control parameter set by the charge / discharge power control unit 213 can be the determination of the control gain (for example, the proportionality constant in the case of proportional control) of the FB control performed using the control target value and the power value at the measurement point. Specifically, the charge / discharge power control unit 213 determines the control gain related to output control in its own device based on the ratio of its own device to a predetermined index (for example, the number of energy storage PCS 20s) that applies to all energy storage PCS 20s operating in the power supply system 1. More specifically, for example, if there are two energy storage PCS 20s operating in the power supply system 1, including its own device, the ratio of its own device to the total will be 1 / 2. In this case, the charge / discharge power control unit 213 determines the control gain related to output control in its own device by multiplying the control gain (hereinafter also referred to as the reference control gain, etc.) which is set in advance for the entire power supply system 1 by its own device's ratio of 1 / 2.

[0053] Once the control parameters for AC power output control are set in this manner, the energy storage PCS 20 (its control unit 21) starts output control based on those parameters (S105). The energy storage PCS 20 also continues to perform output control and, while monitoring the increase or decrease of other energy storage PCS 20s operating within the power supply system 1, executes a subroutine to readjust the control parameters according to the increase or decrease (step S106). Then, when predetermined termination conditions are met, such as receiving a command signal to stop operation, the operation is stopped and the series of processes is terminated.

[0054] (Monitoring the increase / decrease in other devices) Next, the subroutine in step S106 will be explained with reference to Figure 6. Figure 6 is a flowchart showing the flow of the subroutine in step S106 in the control processing of the energy storage PCS20 according to this embodiment. As shown in Figure 6, in the subroutine, the energy storage PCS20 (other device information receiving unit 212) first receives information relating to the operating status of other energy storage PCS20s in the system (S201). Next, the control unit 21 performs a process to determine whether or not there is a device that has newly started operation based on the information acquired in step S201 (S202).

[0055] Here, if the control unit 21 determines that there is a device that has started operation, it will then... Output control is temporarily suspended (S203), and the charge / discharge power control unit 213 resets the control parameters based on the acquired information (S204). Specifically, if another energy storage PCS20 has started operation and the number of operating energy storage PCS20 increases by one (for example, from two to three), the ratio of the device itself among all operating energy storage PCS20 decreases (for example, from 1 / 2 to 1 / 3). The charge / discharge power control unit 213 then multiplies the ratio of the device itself, which has changed in this way, by the reference control gain to determine (reset) the control gain related to the output control of the device itself. Then, once the new control parameters are set in step S204, the energy storage PCS20 (control unit 21) resumes output control with the new control parameters (S208), and the subroutine processing is temporarily terminated.

[0056] On the other hand, if the control unit 21 determines in step S202 that there are no newly started-upon energy storage PCS20 units, it performs a process to determine whether or not there are any energy storage PCS20 units that have stopped operating, based on the information acquired in step S201 (S205).

[0057] If the control unit 21 determines that there is a power storage PCS 20 that has stopped operating, it temporarily suspends the output control of its own device (S206), and the charge / discharge power control unit 213 resets the control parameters based on the acquired information (S207). Specifically, if there is another power storage PCS 20 that has stopped operating and the number of operating power storage PCS 20 decreases by one (for example, from two to one), the ratio of its own device among all operating power storage PCS 20 increases (for example, from 1 / 2 to 1 / 1). The charge / discharge power control unit 213 then multiplies the ratio of its own device, which has changed in this way, by the reference control gain to determine (reset) the control gain related to the output control of its own device. Then, when the new control parameters are set in step S207, the power storage PCS 20 (control unit 21) resumes output control with the new control parameters (S208), and the subroutine processing ends for the time being.

[0058] On the other hand, if the control unit 21 determines in step S205 that there are no other energy storage PCS 20s that have stopped operating, the energy storage PCS 20 will terminate the processing of the subroutine. The subroutine described above in step S106 is executed repeatedly at all times while the energy storage PCS 20 is in operation.

[0059] (Automatic setting of control parameters when the number of units increases) Next, based on Figure 7, we will explain the changes in the control state of each energy storage PCS20 when the number of operational energy storage PCS20 in power supply system 1 increases. Figure 7 is a time chart that explains the process when the number of operational energy storage PCS20 in power supply system 1 increases. In the following explanation, we will refer to energy storage PCS20a as the first unit in Figure 7, energy storage PCS20b as the second unit, and energy storage PCS20c as the third unit.

[0060] As shown in Figure 7, each energy storage PCS20 performs a "unit count" to determine how many energy storage PCS20 units, including its own, are in operation within the system. In this count, each energy storage PCS20 uses its own unit as the initial value. Each energy storage PCS20 may be able to receive information regarding the operating status of other units even before the operation command is turned ON. Figure 7 is explained based on this premise.

[0061] First, when the power storage PCS20a is switched from a stopped state to an ON state, it starts operating. At this time, the other power storage PCS20b and PCS20c have not yet started operating, so the unit count is 1 unit, which is its own unit. Then, the power storage PCS20a transmits information to the power storage PCS20b and PCS20c, including that it is in operation and its own unique unit number (e.g., 001). Upon receiving this information, the power storage PCS20b and PCS20c each increment their unit count by 1, changing it to 2 units.

[0062] The PCS20a energy storage system determines its own control gain based on the information of one unit count. Specifically, as described above, it sets the control parameter as the control gain for its own output control by multiplying the reference control gain by its own ratio (1 / 1). Then, based on this control parameter (control content), it starts output control.

[0063] Next, the energy storage PCS20b switches from a stopped state to an ON state when the operation command is turned ON and it starts operating. At this time, since the energy storage PCS20a is already in operation, the unit count of the energy storage PCS20b is 2 units. The energy storage PCS20b then transmits information to the energy storage PCS20a and energy storage PCS20c, including that it is in operation and its unit number (for example, 002). Upon receiving this information, the energy storage PCS20a and energy storage PCS20c each increment their unit count by 1 unit. As a result, the unit count of the energy storage PCS20a becomes 2 units and the unit count of the energy storage PCS20c becomes 3 units.

[0064] Here, the energy storage PCS20b determines the control gain for its own output control based on the information from the unit count of 2 units. That is, as described above, it sets the control parameter as the control gain for its own output control by multiplying the reference control gain by its own ratio (1 / 2). Then, based on this control parameter, it starts output control.

[0065] Meanwhile, after receiving information about the operating status from the energy storage PCS20b, the energy storage PCS20a temporarily stops output control (the blacked-out area in the diagram) and changes its own control gain based on the unit count of 2. Specifically, it resets the control parameter to the control gain for its own unit, which is the reference control gain multiplied by its own unit's ratio (1 / 2). Then, it resumes output control based on this control parameter.

[0066] Next, the energy storage PCS20c is switched from a stopped state to an ON state and begins operation. At this time, since energy storage PCS20a and energy storage PCS20b are already in operation, the unit count of energy storage PCS20c is 3. Then, energy storage PCS20c transmits information to energy storage PCS20a and energy storage PCS20b, including that it is in operation and its unit number (for example, 003). Upon receiving this information, energy storage PCS20a and energy storage PCS20b each increment their unit count by 1. As a result, the unit counts of energy storage PCS20a and energy storage PCS20b become 3.

[0067] Here, the energy storage PCS20c determines its own control gain for output control based on the information from the unit count of 3 units. Specifically, it sets the control parameter as the control gain for output control of its own unit by multiplying the reference control gain by its own ratio (1 / 3). Then, based on this control parameter, it starts output control.

[0068] Meanwhile, after receiving information about the operating status from the energy storage PCS20c, the energy storage PCS20a and PCS20b temporarily stop output control and change their own control gains based on the unit count of 3. Specifically, they reset their control parameters to a value obtained by multiplying the reference control gain by their own ratio (1 / 3) as the control gain for their own output control. Then, they resume output control based on these control parameters.

[0069] Through the above process, even if the number of operating energy storage PCS20 units in power supply system 1 increases, each energy storage PCS20 can automatically set (determine and change) its control parameters, enabling optimized output control for the entire system.

[0070] (Automatic setting of control parameters when the number of units decreases) Next, based on Figure 8, we will explain the changes in the control state of each energy storage PCS20 when the number of operational energy storage PCS20 in power supply system 1 decreases. Figure 8 is a time chart that explains the process when the number of operational energy storage PCS20 in power supply system 1 decreases. In the following explanation, we will refer to energy storage PCS20a as the first unit in Figure 8, energy storage PCS20b as the second unit, and energy storage PCS20c as the third unit.

[0071] In Figure 8, initially, all three energy storage PCS20a, PCS20b, and PCS20c are operational, so the unit count for each PCS20 is 3. From this state, the operation command for PCS20a is turned OFF, and it stops operating. As a result, the transmission of information related to the operating status of PCS20a is also stopped, and PCS20b and PCS20c can no longer receive information related to the operating status of PCS20a. Then, PCS20b and PCS20c, which can no longer receive information related to the operating status of PCS20a, each reduce their unit count by 1, changing it to 2.

[0072] Following the change in the unit count to 2, the energy storage PCS20b and PCS20c temporarily stop their output control (blacked-out area in the diagram) and change their control gains based on the unit count of 2. Specifically, they reset their control parameters to a value obtained by multiplying the reference control gain by the ratio of their own unit (1 / 2), and then restart output control based on these new control parameters.

[0073] Next, the power storage PCS20b is turned OFF and stops operating. As a result, the transmission of information related to the operating status of the power storage PCS20b also stops, and power storage PCS20a and PCS20c can no longer receive information related to the operating status of the power storage PCS20b. Then, power storage PCS20a and PCS20c, which can no longer receive information related to the operating status of the power storage PCS20b, each deduct one unit from their unit count. As a result, the unit count of power storage PCS20a becomes 2 units, and the unit count of power storage PCS20c becomes 1 unit.

[0074] Then, the PCS20c, having changed the unit count to 1, temporarily stops output control and changes its own control gain based on the unit count of 1. Specifically, it resets the control parameter as the control gain for its own output control, which is the value obtained by multiplying the reference control gain by its own ratio (1 / 1). Then, it resumes output control based on this control parameter.

[0075] Next, the power storage PCS20c is turned OFF and stops operating. As a result, the transmission of information related to the operating status of the power storage PCS20c also stops, and power storage PCS20a and PCS20b can no longer receive information related to the operating status of the power storage PCS20c. Then, power storage PCS20a and PCS20b, which can no longer receive information related to the operating status of the power storage PCS20c, each deduct one unit from their unit count. As a result, the unit count of power storage PCS20a, PCS20b, and PCS20c each returns to the initial value of 1 unit for their own device.

[0076] Furthermore, in this state, all energy storage PCS20 in power supply system 1 are shut down, so the only power supplied to load 50 is from the commercial power grid 80.

[0077] Through the above process, even if the number of operating energy storage PCS20 units decreases in the power supply system 1, each energy storage PCS20 can automatically set (determine and change) its control parameters, enabling optimized output control for the entire system.

[0078] As described above, according to this embodiment, each energy storage PCS in the system can automatically determine its control gain based on information regarding the operating status of other energy storage PCS. This allows each energy storage PCS to automatically set its control parameters and perform optimized output control for the entire system, even if an operating energy storage PCS stops due to an unforeseen event such as a malfunction. Furthermore, even when starting up a new energy storage PCS, it is not necessary to manually set the control parameters of each energy storage PCS each time, thus reducing the effort required to configure the energy storage PCS.

[0079] (modified version) In the above embodiment, each energy storage PCS20 determined its own control gain by multiplying its ratio to the total number of energy storage PCS20s operating in the system by the reference control gain. However, the control gain of a device may be determined by other methods. For example, the ratio of the device's rated capacity to the sum of the rated capacities of the operating energy storage PCS20s may be multiplied by the reference control gain. Specifically, if the rated capacity of energy storage PCS20a in the power supply system 1 is 2kW, the rated capacity of energy storage PCS20b is 4kW, and the rated capacity of energy storage PCS20c is 2kW, and all of the energy storage PCS20s are operating, the "sum of the rated capacities of the operating energy storage PCS20s" will be 8kW. In this case, the ratio of the rated capacity of the device of energy storage PCS20a is 2 / 8, the ratio of the rated capacity of the device of energy storage PCS20b is 4 / 8, and the ratio of the rated capacity of the device of energy storage PCS20c is 2 / 8. Then, by multiplying the ratio calculated in this way by the reference control gain, each energy storage PCS20 can determine the control gain related to output control in its own device.

[0080] Furthermore, in the above method, the control gain of the device was determined by calculating the ratio of the device itself each time in accordance with the increase or decrease in the number of operating energy storage PCS20, and then multiplying the reference control gain by the calculated ratio. However, other methods can also be adopted. Specifically, for example, the energy storage PCS20 may maintain a table in an auxiliary storage device 103 or the like that defines the control gain of the device itself according to the number of operating energy storage PCS20 (or the sum of the rated capacities), and determine the control gain of the device itself by referring to this table.

[0081] <Other> The embodiments described above are merely examples, and the disclosure of these embodiments can be modified as appropriate without departing from the gist of the invention. Furthermore, the processes and means described in this disclosure can be freely combined and implemented as long as no technical inconsistencies arise. For example, in the embodiments described above, the case in which there are three energy storage devices (energy storage PCS) installed in the system was described as an example, but the number of energy storage devices is not limited to this and can be any number. Rather, when applying the present invention, stable output control of the entire system can be performed regardless of how many energy storage devices are used, so it is suitable when there are many energy storage devices.

[0082] Furthermore, in the above embodiment, an example was described in which the output control of the entire system is optimized by changing the control gain in the output control of the device based on the ratio of the device itself to a predetermined index that applies to all energy storage PCS operating within the power supply system. However, the output control of the entire system may also be adjusted by adjusting parameters other than the control gain. Specifically, for example, the upper and lower limits of a control target value (with a range) defined by upper and lower limits may be changed. In this case, for example, the upper and lower limits can be changed so that the range of the control target widens if the number of energy storage PCS operating in the system increases, and so that the range of the control target narrows if the number decreases. Another example is to change the limit value of the output power at which a limiter provided in each energy storage PCS activates.

[0083] Furthermore, although the above embodiment described a case where the power supply system is equipped only by a storage battery, the present invention can also be applied to power supply systems that are equipped with other power sources (power generation devices) instead of or in addition to a battery. Even in power supply systems with power generation equipment, the present invention is suitable for application if it is a self-consumption type power system where reverse power flow to the commercial power grid is prohibited. In particular, when a power generation facility that uses natural energy such as solar power as a power source is equipped, the present invention is suitable for application because interruptions in power supply from the power generation facility (stoppage of the power control device) can occur frequently.

[0084] Furthermore, in the above explanation, processes described as being performed by a single device may be divided and executed by multiple devices. Conversely, processes described as being performed by different devices may be executed by a single device. In a computer system, the hardware configuration used to implement each function can be flexibly changed.

[0085] <Computer-readable recording medium> A program that enables any of the above functions to be implemented in an information processing device or other machine or device (hereinafter referred to as a computer, etc.) can be recorded on a recording medium that the computer, etc. can read. Then, by having the computer, etc. read and execute the program on this recording medium, the function can be provided.

[0086] Here, a recording medium that can be read by a computer refers to a recording medium that stores information such as data and programs through electrical, magnetic, optical, mechanical, or chemical means and can be read by a computer. Examples of such recording media that can be removed from a computer include flexible disks, magneto-optical disks, CD-ROMs, CD-R / Ws, DVDs, Blu-ray discs, DATs, 8mm tapes, memory cards such as flash memory, and external SSDs (Solid State Drives). In addition, recording media that are fixed to a computer include SSDs, hard disks, and ROMs.

[0087] <Note 1> A power supply system (1) that is connected to a commercial power grid and includes multiple power supply facilities (2) that are connected to a commercial power grid and equipped with a power supply (27) and a power supply control device (20) that controls the power output from the power supply, and is capable of supplying AC power to a load, The power control devices of each of the aforementioned power supply facilities have a communication path (31) that enables them to communicate information with each other. Each of the aforementioned power control devices is: A self-device operating status transmission unit (211) transmits information relating to the operating status of the self-device via the aforementioned communication path, A receiving unit (212) for the operating status of other devices receives information relating to the operating status of other power control devices via the aforementioned communication path, An output control unit (213) that uses information relating to the operating status of the aforementioned other power control devices to determine a predetermined value relating to power output control from the power supply that is the control target of its own device, A power supply system characterized by comprising the following features.

[0088] <Note 2> A control method for each power control device in a power supply system that includes multiple power supply facilities capable of supplying AC power to a load, each of which is connected to a commercial power grid and includes a power supply and a power control device that controls at least the power output from the power supply, A step (S101) to acquire information on other devices, which is used to acquire information on the operating status of other power control devices included in the power supply system, The self-device information output step (S103) outputs information related to the operating status of the self-device, A control parameter setting step (S104) in which a predetermined numerical value related to power output control from the power supply that is the control target of the device is determined using information relating to the operating status of the other power control devices, A control method for a power supply control device, characterized by having the following features. [Explanation of Symbols]

[0089] 1. Power System 2, 2a, 2b, 2c...Energy storage equipment 20, 20a, 20b, 20c...Energy storage PCS 21... Control Unit 22. Bidirectional DC / DC Converter 23. Bidirectional DC / AC Inverter 27, 27a, 27b, 27c... Battery storage units 50...load 80...Commercial power system 82...wattmeter 101... Processor 102...Main memory 103...Auxiliary storage device 104...Communication IF 105... Input / Output Interface 106... Connecting bus

Claims

1. A power supply system comprising multiple power supply facilities that are connected to a commercial power grid and equipped with a power supply and a power control device that controls at least the power output from the power supply, and capable of supplying AC power to a load, A communication path that connects the power control devices of each of the aforementioned power supply facilities in a manner that enables them to communicate with each other, A measuring means for measuring at least a physical quantity related to power at a measurement point between the commercial power system and the load, It has, Each of the aforementioned power control devices is: A device operating status transmission unit that transmits information relating to the operating status of the device via the aforementioned communication path, A receiving unit for the operating status of other devices receives information relating to the operating status of other power control devices via the aforementioned communication path. An output control unit that controls the power output from the power supply that is the control target of the device by feedback control using information relating to the operating status of the other power control device, a power control target value at the measurement point that is set in advance so as not to cause reverse power flow to the commercial power grid, and a state quantity calculated based on the physical quantity obtained from the measurement means, Equipped with, The output control unit determines the control constants related to the feedback control based on the ratio of its own device to a predetermined index that applies to the entire power control device operating within the power system. A power supply system characterized by the following features.

2. The predetermined indicator is the number of power control devices. The power supply system according to claim 1, characterized in that...

3. The power control device is a power conditioner, and the predetermined indicator is the rated capacity related to the output power of the power conditioner. The power supply system according to claim 1, characterized in that...

4. The power supply system according to any one of claims 1 to 3, characterized in that the power supply includes a storage battery.

5. A control method for each power control device in a power supply system that is connected to a commercial power grid and includes multiple power supply facilities capable of supplying AC power to a load, each power control device being connected to a commercial power grid and equipped with a power source and a power control device that controls at least the power output from the power source, A step of acquiring information on other devices, which acquires information relating to the operating status of other power control devices included in the power supply system, A self-device information output step that outputs information related to the operating status of the self-device, A control parameter setting step in which a predetermined numerical value related to power output control from the power supply that is the control target of the device is determined using information relating to the operating status of the other power control device, It has, The predetermined numerical value is a control constant related to feedback control using a pre-set control target value and state variable. In the control parameter setting step, the control constant is determined based on the ratio of the device to a predetermined index that applies to the entire power control device operating within the power system. A control method for a power supply control device, characterized by the above.

6. The predetermined indicator is the number of power control devices. A control method for a power supply control device according to claim 5, characterized in that

7. The power control device is a power conditioner, and the predetermined indicator is the rated capacity related to the output power of the power conditioner. A control method for a power supply control device according to claim 5, characterized in that

8. A control method for a power supply control device according to any one of claims 5 to 7, characterized in that the power supply includes a storage battery.

9. A program for causing a power control device to perform each step of the control method for a power control device according to any one of claims 5 to 7.

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