Power control device, power system, method for controlling power control device, and method for controlling central control device

Abstract

The present invention suppresses complexity of a power converter and realizes control based on a reference function. The power control device controls a power converter that converts and outputs input power, and is provided with: a setting unit that sets the control mode of the power converter to any one of constant voltage control, constant current control, constant power control, and output stop in accordance with an input value; a target value of an output of the power converter corresponding to the control mode is set based on the control mode and a reference function defined according to an input value; and an output unit that outputs the control mode set by the setting unit and the target value set by the setting unit to the power converter.

Description

Technical Field

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

[0002] As an alternative to large-scale power grids that rely on fossil energy and nuclear energy, power grids that use electricity produced for local consumption have attracted much attention. In power grids that use electricity produced for local consumption, a variety of devices are connected, such as photovoltaic power generation devices (PhotoVoltaic: PV), fixed power storage devices, and electric vehicles (Electric Vehicle: EV). Since each of the above devices is a DC power source, research is underway to build a power grid (DC grid) under direct current (DC).

[0003] As a control method of the DC grid, there is a control method disclosed in Patent Document 1, for example. In this control method, a reference function obtained based on the power (P) at the local end and the voltage (V) at the local end is given to the power converter connected to each of the above-mentioned devices, and the power converter controls the output autonomously and decentralizedly based on the reference function, thereby controlling the DC grid. As a reference function, there is, for example, a reference function that makes the target voltage value have a droop characteristic according to the amount of power required by the DC bus, that is, a reference function with a droop characteristic (droop function). In the method of Patent Document 1, each power converter autonomously and decentralizedly controls the output based on the droop function, so that the load sharing of the power of each device can be implemented according to the amount of power required by the DC bus, and the voltage of the DC bus can be stabilized.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2022-72320 Summary of the invention

[0007] Problems to be solved by the invention

[0008] The power converter disclosed in Patent Document 1 stores a droop function, and a control unit controls a power conversion unit that performs power conversion between a device and a DC bus based on the stored reference function, thereby controlling input and output to the DC bus. That is, in this power converter, it is necessary to have a storage unit that stores the droop function and a control function based on the droop function, and the structure of the power converter as a whole becomes complicated, so it takes time and effort to manufacture and maintain it.

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to realize control based on a reference function while suppressing complexity of a power converter.

[0010] Solutions to Solve Problems

[0011] An electric power control device according to one embodiment of the present invention controls an electric power converter that converts input electric power and outputs the electric power, and comprises: a setting unit that sets the control mode of the electric power converter to any one of constant voltage control, constant current control, constant power control, and output stop in a manner corresponding to an input value, and sets a target value of the output of the electric power converter corresponding to the control mode based on the control mode and a reference function defined according to the input value; and an output unit that outputs the control mode set by the setting unit and the target value set by the setting unit to the electric power converter.

[0012] In the power control device involved in one embodiment of the present invention, the setting unit may set the control mode in a manner corresponding to the reference function, based on a control area that specifies the range of voltage, current and power for constant voltage control, constant current control, constant power control, or output stop according to an input value, and the control area is set in a manner to suppress disturbances of the input value.

[0013] In the power control device according to one aspect of the present invention, the control region may be defined so as to suppress a decrease in efficiency of the power converter.

[0014] In the power control device according to one aspect of the present invention, the setting unit may set the control mode to output stop to suppress a decrease in efficiency of the power converter.

[0015] In the power control device involved in one scheme of the present invention, it may also be that the power control device has a communication unit, which obtains control information indicating the control method of the power converter and a target value of the output of the power converter from an external device. When the control method indicated by the control information is constant power control or constant current control, the setting unit sets the control mode to the control method indicated by the control information, and the output unit outputs the target value obtained by the communication unit and the set control mode to the power converter.

[0016] In an electric power control device involved in one embodiment of the present invention, the electric power control device may also include a region setting unit, which sets a control region that specifies the range of voltage, current and power for constant voltage control, constant current control, constant power control, or output stop according to an input value in a manner corresponding to the reference function. When the control method represented by the control information is constant voltage control, the setting unit sets the control mode specified by the control region corresponding to the target value and the target value determined according to the reference function, and the output unit outputs the set control mode and the target value to the power converter.

[0017] An electric power system involved in one scheme of the present invention comprises: the electric power control device; and a power converter, which obtains the control mode and the target value from the electric power control device, and when the acquired control mode is constant voltage control or constant power control, performs control corresponding to the acquired control mode based on the acquired target value, and stops output when the control mode is output stop.

[0018] A control method for an electric power control device according to one embodiment of the present invention is a control method for an electric power control device that controls an electric power converter that converts input electric power and outputs the electric power, and comprises: a setting step of setting the control mode of the electric power converter to any one of constant voltage control, constant power control, and output stop in a manner corresponding to an input value, and setting a target value of the output of the electric power converter corresponding to the control mode based on the control mode and a reference function defined according to the input value; and an output step of outputting the control mode set by the setting step and the target value set by the setting step to the electric power converter.

[0019] A control method for a central control device according to one embodiment of the present invention controls a power control device of a power converter that converts input power and outputs it, wherein the power control device comprises: a setting unit that sets the control mode of the power converter to any one of constant voltage control, constant current control, constant power control, and output stop in a manner corresponding to an input value, and sets a target value of the output of the power converter corresponding to the control mode based on the control mode and a reference function defined according to the input value; and an output unit that outputs the control mode set by the setting unit and the target value set by the setting unit to the power converter, and the control method for the central control device comprises a step of causing the central control device to output the reference function to the power control device.

[0020] Effects of the Invention

[0021] According to the present invention, it is possible to realize control based on a reference function while suppressing complication of the power converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a diagram showing a configuration of a power system according to an embodiment.

[0023] Figure 2 It is a diagram showing the structure of a power converter.

[0024] Figure 3 It is a diagram showing the structure of the functional part of the power converter.

[0025] Figure 4 It is a diagram showing the structure of a power control device.

[0026] Figure 5 : is a diagram showing an example of a reference function and a control area.

[0027] Figure 6 : is a diagram showing an example of a reference function and a control area.

[0028] Figure 7 : is a diagram showing an example of a reference function and a control area.

[0029] Figure 8 This is a flowchart showing the flow of processing performed by the control unit of the power control device.

[0030] Fig. 9 : is a diagram showing an example of a reference function and a control area.

[0031] Fig.10 This is a sequence diagram showing an example of a control method of a power system.

[0032] Fig.11 It is a diagram showing a configuration of a power control device according to a second embodiment.

[0033] Fig.12 This is a flowchart showing the flow of processing performed by the control unit of the power control device.

[0034] Fig.13A This is a diagram showing an example of a reference function.

[0035] Fig. 13B It is a diagram showing an example of a reference function and a control area.

[0036] Fig.14A It is a diagram showing an example of a reference function, a control area, and an operating point.

[0037] Fig. 14BIt is a diagram showing an example of a reference function, a control area, and an operating point.

[0038] Fig.15A It is a diagram showing an example of a reference function, a control area, and an operating point.

[0039] Fig. 15B It is a diagram showing an example of a reference function, a control area, and an operating point.

[0040] Fig.16A It is a diagram showing an example of a reference function, a control area, and an operating point.

[0041] Fig. 16B It is a diagram showing an example of a reference function, a control area, and an operating point.

[0042] Fig.17A This is a diagram showing an example of a reference function.

[0043] Fig. 17B It is a diagram showing an example of a reference function and a control area.

[0044] Fig.18A This is a diagram showing an example of a reference function.

[0045] Fig.18B It is a diagram showing an example of a reference function and a control area.

[0046] Fig.19A This is a diagram showing an example of a reference function.

[0047] Fig.19B It is a diagram showing an example of a reference function and a control area.

[0048] Fig. 20A This is a diagram showing an example of a reference function.

[0049] Fig. 20B It is a diagram showing an example of a reference function and a control area.

[0050] Fig.21A This is a diagram showing an example of a reference function.

[0051] Fig. 21B It is a diagram showing an example of a reference function and a control area.

[0052] Fig.22A This is a diagram showing an example of a reference function.

[0053] Fig. 22B It is a diagram showing an example of a reference function and a control area. DETAILED DESCRIPTION

[0054] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the present invention is not limited to the embodiments described below. In the description of the accompanying drawings, the same reference numerals are appropriately marked on the same parts.

[0055] (First embodiment)

[0056] <Electricity System Structure>

[0057] Figure 1 1 is a diagram showing a configuration of a power system according to an embodiment. A power system 1 includes power converters 11 to 15, power elements 21 to 25, power control devices 51 to 55, and a bus 30. The power system 1 also includes an EMS (Energy Management System) 40. The EMS 40 is an example of a central control device.

[0058] The power converters 11 to 13 and 15 are DC / DC converters that convert a DC voltage. The power converter 14 is an AC / DC converter that converts a DC voltage into an AC voltage. Commercially available power converters can be used for the power converters 11 to 15. The output of the power converter 11 is controlled by a power control device 51, the output of the power converter 12 is controlled by a power control device 52, and the output of the power converter 13 is controlled by a power control device 53. In addition, the output of the power converter 14 is controlled by a power control device 54, and the output of the power converter 15 is controlled by a power control device 55.

[0059] The bus 30 is a DC bus in the power system 1, and is connected to the power converters 11 to 15. In the power system 1, a power network including a DC grid composed of the bus 30, the power converters 11 to 15, and the power elements 21 to 25 is formed.

[0060] The power element 21 is, for example, a fixed power storage device capable of charging and discharging electric power, and is connected to the power converter 11. The fixed power storage device is an example of a permanent in-equipment power storage device. The power converter 11 has the following functions: converting the voltage of the DC power supplied by the power element 21 and outputting it to the bus 30, and converting the voltage of the DC power supplied from the bus 30 and outputting it to the power element 21 to charge it. The output of the power converter 11 is controlled by the power control device 51. The power control device 51 has the function of performing information communication by wire or wireless. The power control device 51 communicates with the EMS 40 and the power converter 11, and controls the output of the power converter 11 based on the reference function sent from the EMS 40 and stored.

[0061] The power element 22 is, for example, a solar power generation device capable of generating and supplying electric power, and is connected to the power converter 12. The solar power generation device is an example of a power generation device that generates electric power using renewable energy. The power converter 12 has a function of converting the voltage of the DC power supplied by the power element 22 and outputting it to the bus 30. The output of the power converter 12 is controlled by the power control device 52. The power control device 52 has a function of performing information communication by wire or wireless. The power control device 52 communicates with the EMS 40 and the power converter 12, and controls the output of the power converter 12 based on the reference function sent from the EMS 40 and stored.

[0062] The power element 23 is, as an example, an on-board power storage device capable of supplying, consuming and charging power, and is connected to the power converter 13. The on-board power storage device is mounted on the electric vehicle EV and is an example of a mobile non-stationary power storage device. The power converter 13 has the following functions: converting the voltage of the DC power supplied by the power element 23 and outputting it to the bus 30, and converting the voltage of the DC power supplied from the bus 30 and outputting it to the power element 23 to charge it. The power converter 13 is, for example, set at a charging station or a residential charging device, but it can also be mounted on the electric vehicle EV. The output of the power converter 13 is controlled by the power control device 53. The power control device 53 has the function of performing information communication by wire or wireless. The power control device 53 communicates with the EMS 40 and the power converter 13, and controls the output of the power converter 13 based on the reference function sent from the EMS 40 and stored.

[0063] The power element 24 is, for example, a commercial power system, and is connected to the power converter 14. The power converter 14 converts the AC power supplied by the power element 24 into DC power and outputs it to the bus 30, and converts the DC power supplied from the bus 30 into AC power and outputs it to the power element 24. The output of power from the bus 30 to the power element 24 is also called reverse flow. The output of the power converter 14 is controlled by the power control device 54. The power control device 54 has a function of performing information communication by wire or wireless. The power control device 54 communicates with the EMS 40 and the power converter 14, and controls the output of the power converter 14 based on the reference function sent from the EMS 40 and stored.

[0064] The power element 25 is, for example, a ZEH (Net Zero Energy House) that can supply, consume, and charge power, and is connected to the power converter 15. The ZEH includes, for example, a solar power generation device or a storage battery, and electrical products such as an air conditioner or a refrigerator as a power load. The power converter 15 has the following functions: converting the voltage of the DC power supplied by the power element 25 and outputting it to the bus 30, and converting the voltage of the DC power supplied from the bus 30 and outputting it to the power element 25, so as to charge the storage battery and operate the power load. The power control device 55 has the function of performing information communication via wired or wireless communication. The power control device 55 communicates with the EMS 40 and the power converter 15, and controls the output of the power converter 15 based on the reference function sent from the EMS 40 and stored.

[0065] The EMS 40 has a function of comprehensively managing the state of the power system 1 . The EMS 40 includes a control unit 41 , a storage unit 42 , and a communication unit 43 .

[0066] The control unit 41 is a component that performs various calculations for realizing the functions of the EMS 40, and is composed of processors such as a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), a DSP (Digital Signal Processor), and a GPU (Graphics Processing Unit). The functions of the control unit 41 are realized as a functional unit by the control unit 41 reading and executing various programs from the storage unit 42.

[0067] The storage unit 42 includes, for example, a ROM (Read Only Memory) for storing various programs and data used by the control unit 41 for performing calculation processing. In addition, the storage unit 42 includes, for example, a RAM (Random Access Memory) for storing a work space when the control unit 41 performs calculation processing, the results of the calculation processing of the control unit 41, etc. The storage unit 42 may also include an auxiliary storage device such as a HDD (Hard Disk Drive) or an SSD (Solid State Drive).

[0068] The communication unit 43 is configured to include a communication module that performs information communication by wire or wirelessly. The communication unit 43 performs information communication with the power control devices 51 to 55 and the external server 60 via a network NW constituted by the Internet network, a mobile phone network, or the like.

[0069] It should be noted that the external server 60 is a server provided outside the power system 1. The external server 60 is, for example, an information processing device configured to function as an EMS in another power system, or an information processing device having a database and functioning as a data server for the EMS 40. The external server 60 stores various information that may affect the operation of the power system 1.

[0070] <Structure of power converter>

[0071] Next, the specific structure of the power converter 11 will be described. Figure 2 2 is a diagram showing a configuration of the power converter 11. The power converter 11 includes a power conversion unit 100a, a sensor 100b, a control unit 100c, and a communication unit 100d.

[0072] The power conversion unit 100a performs DC / DC conversion to convert the voltage of the DC power input from the discharged power element 21 and output it to the bus 30. The power conversion unit 100a can also convert the voltage of the DC power input from the bus 30 and output it to the power element 21 to charge the power element 21. The power conversion unit 100a is composed of, for example, a circuit including a coil, a capacitor, a diode, a switching element, etc. The switching element is, for example, a field effect transistor or an insulated gate bipolar transistor. The power conversion unit 100a can control the power conversion characteristics by, for example, PWM (Pulse Width Modulation) control.

[0073] The sensor 100b measures the electrical characteristic value of the power on the bus 30 side of the power conversion unit 100a. Therefore, the sensor 100b measures the electrical characteristic value of the power input to or output from the power converter 11. The sensor 100b can measure a current value, a voltage value, a power value, etc. as the electrical characteristic value. The sensor 100b outputs the measured electrical characteristic value to the control unit 100c.

[0074] The communication unit 100d is configured to include a communication module that performs information communication by wire or wireless and a communication control unit that controls the operation of the communication module. The communication unit 100d performs information communication with the power control device 51 by wired communication or wireless communication. The communication unit 100d receives a control mode and a target value from the power control device 51 and outputs them to the control unit 100c. In addition, the communication unit 100d transmits the electrical characteristic value input from the control unit 100c to the power control device 51, for example. The electrical characteristic value input by the control unit 100c to the communication unit 100d is the electrical characteristic value obtained by the control unit 100c from the sensor 100b.

[0075] The control unit 100c is configured to include a processor and a storage unit that perform various calculations for controlling the operation of the power conversion unit 100a. The processor and the storage unit can use the components exemplified as the configuration of the control unit 41 and the storage unit 42, respectively. The functions of the control unit 100c are realized as a functional unit by the processor reading and executing various programs from the storage unit.

[0076] Figure 3 1 is a diagram showing the functional units involved in the present invention implemented in the control unit 100c. The control unit 100c includes an operation amount setting unit 100ca and an information providing unit 100cb as functional units implemented in a software manner by executing a program. The information providing unit 100cb obtains the electrical characteristic value output from the sensor 100b and outputs the obtained electrical characteristic value to the communication unit 100d.

[0077] The operation amount setting unit 100ca outputs the control mode received by the communication unit 100d from the power control device 51 to the power conversion unit 100a. As the control mode, there are a constant power mode in which the output of the power conversion unit 100a is controlled to the power of the target value, a constant voltage mode in which the output of the power conversion unit 100a is controlled to the voltage of the target value, and a stop mode in which the output of the power conversion unit 100a is stopped. In addition, the operation amount setting unit 100ca performs feedback control to set the operation amount (for example, duty cycle) for PWM control in such a way that the difference between the electrical characteristic value measured by the sensor 100b and the target value received by the communication unit 100d from the power control device 51 is within a prescribed range. The target value is, for example, a voltage value or a power value. The operation amount setting unit 100ca outputs the information of the set operation amount to the power conversion unit 100a to control the power conversion unit 100a. The feedback control performed by the operation amount setting unit 100ca can be performed using a known method such as PID control that reads and executes parameters such as proportional gain, integral time, and differential time pre-stored in the storage unit.

[0078] It should be noted that the other power converters 12, 13, 14, and 15 may also have the same structure as the power converter 11. However, the power conversion unit 100a of the power converter 14 performs AC (Alternating Current) / DC conversion to convert the AC power supplied from the power element 24 into DC power and output it to the bus 30, and DC / AC conversion to convert the DC power supplied from the bus 30 into AC power and output it to the power element 24.

[0079] <Structure of power control device>

[0080] Next, the specific structure of the power control device 51 will be described. Figure 42 is a diagram showing a configuration of a power control device 51. The power control device 51 includes a control unit 500a, a storage unit 500b, and a communication unit 500c.

[0081] The communication unit 500c is configured to include a communication module that performs information communication by wire or wireless and a communication control unit that controls the operation of the communication module. The communication unit 500c performs information communication with the power converter 11 by wired communication or wireless communication. The communication unit 500c, for example, sends the control mode and target value to the power converter 11, and outputs the electrical characteristic value sent from the power converter 11 to the control unit 500a. In addition, the communication unit 500c communicates with the EMS 40 via the network NW. The communication unit 500c sends the electrical characteristic value sent from the power converter 11 to the EMS 40, and receives the reference function information and control area information sent from the EMS 40. The reference function information and control area information received by the communication unit 500c are stored in the storage unit 500b. The reference function information is various information for specifying the droop function constituting the reference function. The control area information is information for specifying the control mode of the power converter 11.

[0082] The storage unit 500b has a nonvolatile memory and stores the reference function information and the control region information received by the communication unit 500c. The storage unit 500b also stores the program executed by the control unit 500a.

[0083] The control unit 500a is configured to include a processor that performs various calculation processes for controlling the operation of the power control device 51. The processor can use the components exemplified as the structure of the control unit 41. The functions of the control unit 500a are realized as a functional unit by the processor reading out various programs from the storage unit 500b and executing them. For example, the control unit 500a determines the target value of the output of the power converter 11 and the control mode of the power converter 11 based on the reference function information stored in the storage unit 500b, the control area information stored in the storage unit 500b, and the electrical characteristic value sent from the power converter 11.

[0084] The control unit 500a includes a setting unit 500aa and an output unit 500ab as functional units implemented in software by executing a program. The setting unit 500aa sets the control mode of the power converter 11 based on the electrical characteristic value obtained from the power converter 11 and the control region information stored in the storage unit 500b. In addition, the setting unit 500aa sets the target value of the output of the power converter 100a based on the reference function information and control region information stored in the storage unit 500b and the electrical characteristic value received by the communication unit 500c. The output unit 500ab outputs the control mode and target value set by the setting unit 500aa to the power converter 11.

[0085] It should be noted that the other power control devices 52 to 55 may have the same configuration as the power control device 51. However, the reference function information and the control area information transmitted from the EMS 40 and stored in the storage unit 500b are different information depending on the connected power element.

[0086] <Reference function characteristics>

[0087] Next, the reference function information and the control region information that are the basis for the power control device 51 to control the power converter 11 will be described. Figure 5 This is a diagram showing an example of a reference function indicated by reference function information and a control region indicated by control region information.

[0088] Figure 5 1 is a diagram showing an example of a reference function and a control region that are the basis for controlling the power converter 11 , wherein the vertical axis represents the voltage V and the horizontal axis represents the power P. Figure 5 The reference function shown shows the relationship between the power P and the voltage V on the bus 30 side of the power conversion unit 100a of the power converter 11, that is, the VP characteristic, and shows the power conversion characteristics of the power conversion unit 100a controlled by the power control device 51. It should be noted that when the power conversion unit 100a supplies power to the bus 30, that is, when the power element 21 is in a discharging state, the power P is a positive value, and when the power is supplied from the bus 30, that is, when the power element 21 is in a charging state, the power P is a negative value.

[0089] Figure 5 The reference function represented by the line DL1 shown as being bent in the middle is formed by connecting a plurality of droop functions defined according to the interval of the input value and having different droop characteristics. Specifically, the line DL1 is formed by connecting five droop functions having different droop characteristics, and is identified by reference function information. The reference function information includes, for example, coordinate information of the boundary of the droop function in the coordinates where the horizontal axis is set to P and the vertical axis is set to V, intercept information of the droop function, information on the slope (i.e., the droop coefficient), and information on the shape (straight line, curve, etc.).

[0090] The control unit 500a of the power control device 51 controls the power conversion characteristics of the power converter 11 to become the characteristics of the reference function represented by the line DL1. That is, the control unit 500a of the power control device 51 controls the power converter 11 so that the operating point defined by the electrical characteristic values ​​of the bus 30 side of the power converter 100a, that is, the value of the voltage V and the value of the power P is located on the line DL1.

[0091] It should be noted that the control methods executed by the control unit 500a include droopP control and droopV control. The droopP control is a method in which a target power value Pref is determined as a target value based on the voltage value Vo as an electrical characteristic value received by the communication unit 500c and a reference function, and the difference between the power measured by the sensor 100b and the target power value Pref is made to be below the allowable range. The droopV control is a method in which a target voltage value Vref is determined as a target value based on the power value Po as an electrical characteristic value received by the communication unit 500c and a reference function, and the difference between the voltage measured by the sensor 100b and the target voltage value Vref is made to be below the allowable range.

[0092] The control area determines the control method according to the position of the operating point, and specifies the voltage and power range for corresponding droopP control, droopV control, or output stop according to each reference function. Specifically, the control area is set according to the range of power P and voltage V. Figure 5 In the example shown, area AR11, area AR12, and area AR13 are set. Area AR11 is an area where the operating point is controlled to be on line DL1 by droopP control, and area AR12 is an area where the operating point is controlled to be on line DL1 by droopV control. In addition, area AR13 is an area where the output at the power conversion unit 100a is stopped.

[0093] Figure 6 1 is a diagram showing another example of the reference function and the control region that are the basis for controlling the power converter 11 . Figure 6 The reference function represented by the curved line DL2 shown in the figure is formed by connecting five droop functions having mutually different droop characteristics, and is identified by the reference function information.

[0094] The control unit 500a of the power control device 51 receives reference function information from the EMS 40 and updates the reference function information to Figure 6 In the case of the information shown, the power conversion characteristic of the power converter 11 is controlled to be the characteristic of the reference function represented by the line DL2. That is, the control unit 500a of the power control device 51 controls the power converter 11 so that the operating point is on the line DL2.

[0095] exist Figure 6 In the example shown, area AR21 and area AR22 are set. Area AR21 is an area where control is performed to place the operating point on line DL2 by droopP control, and area AR22 is an area where control is performed to place the operating point on line DL2 by droopV control.

[0096] Figure 7 1 is a diagram showing an example of a reference function and a control region that are the basis for controlling the power converter 14 . Figure 7 The reference function represented by the curved line DL3 shown in the figure is formed by connecting three droop functions having mutually different droop characteristics, and is identified by the reference function information.

[0097] The control unit 500a of the power control device 54 controls the power conversion characteristics of the power converter 14 to be the characteristics of the reference function represented by the line DL3. That is, the control unit 500a of the power control device 54 controls the power converter 14 so that the operating point is on the line DL3.

[0098] exist Figure 7 In the example shown, area AR31 and area AR32 are set. Area AR31 is an area where control is performed to place the operating point on line DL3 by droopP control, and area AR32 is an area where control is performed to place the operating point on line DL3 by droopV control.

[0099] <Control method>

[0100] Next, the control method of the power converters 11 to 15 based on the power control devices 51 to 55 and the control method of the power system 1 are described. In the power system 1, the so-called local control in which the power control devices 51 to 55 are independently and autonomously controlled in a decentralized manner, and the centralized control in which the EMS 40 coordinates and controls the power control devices 51 to 55 according to the power conditions of the power system 1 can be executed. It should be noted that, for example, the local control is repeatedly executed in a shorter cycle, and the centralized control is executed at intervals longer than the cycle of the local control. The local control is also called primary control, and the centralized control is also called secondary control. These control methods, for example, cause a processor to execute a program in each power control device or EMS 40.

[0101] <Local control>

[0102] First, the control method of the power control devices 51 to 55 in the local control will be described by taking the power control device 51 as an example. The same control method as described below can also be appropriately performed in the other power control devices 52 to 55.

[0103] In the control method of the power control device 51, the control unit 500a performs a control step of controlling the power conversion characteristics of the power converter 11, that is, the power conversion characteristics of the power conversion unit 100a, based on the electric characteristic value, the reference function information, and the control region information. An example of the content of the control step is further described in detail with reference to the drawings.

[0104] Figure 84 is a flowchart showing the flow of processing performed by the control unit 500a. The control unit 500a executes, for example, Figure 8 First, the control unit 500a obtains the electric characteristic value received by the communication unit 500c from the power converter 11 (step S101). The electric characteristic value obtained here is an example of an input value. Next, the control unit 500a obtains the reference function information and the control area information from the storage unit 500b (step S102).

[0105] Next, the control unit 500a determines the control method to be executed based on the acquired electrical characteristic value, the reference function information, and the control area information (step S103). Figure 5 When the VP characteristic is located in the region AR11 as shown in FIG. 1 , the control unit 500a determines that the control method to be executed is droopP control. Figure 5 When the operating point OP4 is located in the area AR12 as shown in FIG. Figure 5 When the vehicle is located in the area AR13 as shown, the control unit 500a determines to stop the control.

[0106] Next, the control unit 500a sets the control mode of the power converter 11 based on the determination result of step S103 (step S104). For example, when the control method determined in step S103 is droopP control, in order to simulate droopP control using the power converter 11, the control unit 500a sets the constant power mode as the control mode of the power converter 11. In addition, when the control method determined in step S103 is droopV control, in order to simulate droopV control using the power converter 11, the control unit 500a sets the constant voltage mode as the control mode of the power converter 11. In addition, when it is determined in step S103 that the control is stopped, the setting unit 500aa sets the stop mode as the control mode.

[0107] Next, the control unit 500a sets a target value for the output of the power converter 11 (step S105). Figure 5 When the operating point OP1 is located in the area AR11 as shown in FIG. 1 , the control unit 50a sets the power value P1 of the reference function that intersects when a line is drawn along the horizontal axis from the operating point OP1 as the target value of the constant power mode. Figure 5When the operating point OP2 is located in the area AR12 as shown, the control unit 500a uses the voltage value V11 of the reference function that intersects when a line is drawn along the vertical axis from the operating point OP2 as the target value of the constant voltage mode. It should be noted that when the position of the operating point specified by the acquired electrical characteristic value changes from the position of the operating point OP2 to the position of the operating point OP3, the control unit 500a uses the voltage value V12 of the reference function that intersects when a line is drawn along the vertical axis from the operating point OP3 as the target value of the constant voltage mode. Step S103, step S104, and step S105 are examples of setting steps.

[0108] Next, the control unit 500a transmits the control mode set in step S104 and the target value set in step S105 to the power converter 11 (step S106). Step S106 is an example of an output step.

[0109] The communication unit 100d of the power converter 11 receives the control mode and the target value transmitted from the power control device 51. The control unit 100c of the power converter 11 outputs the control mode received by the communication unit 100d to the power converter 100a. In addition, the control unit 100c sets the operation amount for PWM control so that the difference between the electric characteristic value measured by the sensor 100b and the target value received from the power control device 51 is within a predetermined range, and outputs the set operation amount to the power converter 100a.

[0110] Thus, for example, when the received control mode is the constant power mode and the received target value is the power value P1, the power converter 11 operates in the constant power mode to control the output so that the electrical characteristic value of the bus 30 becomes the power value P1. Also, for example, when the received control mode is the constant voltage mode and the received target value is the voltage value V1, the power converter 11 operates in the constant voltage mode to control the output so that the electrical characteristic value of the bus 30 becomes the voltage value V1. Also, for example, when the received control mode is the stop mode, the power converter 11 stops the operation of the power conversion unit 100a.

[0111] As described above, according to the local control of the present embodiment, even if the power converter 11 is a commercially available power converter, droopP control or droopV control can be simulated by sending the control mode and the target value from the power control device 51 to the power converter 11. Since the power converter 11 can be a commercially available power converter, the structure of the power converter 11 does not become complicated, and the time and effort required for manufacturing and maintenance can be reduced.

[0112] In the local control of the present embodiment, the power control device 51 communicates with the power converter 11, so it takes time from the measurement of the electrical characteristic value of the bus 30 to the control to the target value corresponding to the measured value. Fig. 9 When the area AR12 is formed into a rectangular area sandwiching the line DL1 as shown in FIG. 1 , feedback takes time, so when the operating point moves across the line DL1, the operating point may vibrate. Figure 5 As shown, the region AR12 is set to suppress the disturbance of the operating point. Therefore, even if the operating point moves from the region AR12 to the region AR13 across the line DL1, for example, the power converter 11 is set to the stop mode, so that the vibration of the operating point can be suppressed.

[0113] In addition, for example, if not Figure 5 The control region is set by the reference function shown in FIG. 1 , and droopP control is simulated when the operating point is close to the line DL on the vertical axis, so that the power converter 11 operates under low load. Generally speaking, in DC / DC conversion, the efficiency under low load deteriorates, so if the power converter 11 operates under low load, the efficiency of the entire power network deteriorates. In contrast, in the present embodiment, the control region is set as shown in the figure, and the control region is set in a manner to avoid the operation of the power converter 11 under low load, so the deterioration of the efficiency of the entire power network can be suppressed.

[0114] <Centralized Control>

[0115] Next, centralized control is described. In the example shown below, EMS 40 updates the reference function information and control area information used in the power control devices 51 to 55 according to the instructions, thereby performing centralized control. The so-called updating of the reference function information and the control area information according to the instructions means that the instructions include the reference function information and the control area information related to the reference function, and a part or the whole of the reference function and the control area information are updated according to the instructions. The storage unit 500b of each power control device 51 to 55 can update the reference function information and the control area information.

[0116] For example, in the information communication between EMS 40 and power control devices 51 to 55, the update command for updating the reference function includes the reference function information and control area information. The reference function information and control area information used in the update are stored in the storage unit 42 of EMS 40, and are read and used by the control unit 41 as appropriate.

[0117] Next, refer to Fig.10The timing diagram of the present invention describes an example of a control method for the power system 1 based on centralized control. First, the EMS 40 calls the timer of the local device and starts timing (step S201). Next, the EMS 40 requests the power control devices 51 to 55 for local measurement information (step S202). The local measurement information is an example of information related to the power status of the power system 1, including the electrical characteristic values ​​measured by the sensors 100b of the power converters 11 to 15 and the measurement time of the electrical characteristic values.

[0118] Next, the power control devices 51 to 55 send the local measurement information obtained from the communicating power converters to the EMS 40 (step S203). The EMS 40 stores each local measurement information in the storage unit 42. Next, as an example of information related to the power status of the power system 1, the EMS 40 requests various information that may affect the operation of the power system 1 from the external server 60 (step S204). In this example, the EMS 40 requests the external server 60 for power generation-demand forecast information. The power generation-demand forecast information includes forecast information on power generation in the power system 1 and forecast information on power demand, and may include information such as the season, current weather, and future weather forecast of the region where the power system 1 is installed. In addition, when the external server 60 functions as an EMS of another power system, when the operating status of the other power system may affect the operation of the power system 1, the power generation-demand forecast information may also include forecast information on power generation in the other power system and forecast information on power demand.

[0119] Next, the external server 60 transmits the power generation amount and demand forecast information to the EMS 40 (step S205 ). The EMS 40 stores the power generation amount and demand forecast information in the storage unit 42 .

[0120] Next, the control unit 41 of the EMS 40 reads out the information sent from the storage unit 42, that is, the information related to the power status of the power system 1, and based on this, performs the operation optimization calculation of the power system 1 (step S206). The operation optimization calculation is performed in a manner suitable for various conditions. For example, the power system 1 is controlled to make the bus 30 an operating point of a specified voltage. In this state, it is assumed that the EMS 40 predicts that the future weather in the region where the power element 22 as a solar power generation device is installed will be sunny and the power generation will increase based on the power generation-demand forecast information, and based on the local measurement information obtained from the power converter 12 connected to the power element 22, it is determined that the power element 22 has a surplus in power supply. In this case, the EMS 40 determines to update the reference function of the power control device 51 that controls the power converter 11 connected to the power element 21 so that the power element 21 as a fixed power storage device is charged at this operating point. Furthermore, at the same time as the update, the EMS 40 determines to update the reference function of the power control device 54 that controls the power converter 14 connected to the power element 24 so that power is not supplied from the power element 24 that is the commercial power system.

[0121] In addition, from the perspective of not exceeding the contracted power of the power element 24 as the commercial power system, such as peak shaving and utilization of nighttime power, and from the perspective of appropriate electricity rates, the optimization calculation can be executed under set conditions.

[0122] In addition, the storage unit 42 of the EMS 40 may also store a learned model, and the EMS 40 uses the learned model to perform operation optimization calculations. The learned model can be generated by deep learning using a neural network, for example, using information related to the power status of the power system 1 and the switching and updating results of the reference functions of the corresponding power control devices 51 to 55 as teaching data.

[0123] Next, based on the result of the optimization calculation, the EMS 40 sets reference function information and control area information suitable for the power control device to be updated among the power control devices 51 to 55, and outputs an update instruction including the set reference function information and control area information (step S207). Next, the EMS 40 resets the timer (step S208).

[0124] Next, the power control device to be updated among the power control devices 51 to 55 obtains the update instruction of the reference function and the control area, and updates the reference function information and the control area information (step S209). The power control device that has completed the update of the reference function information and the control area information performs local control (step S210).

[0125] (Variation)

[0126] The embodiments of the present invention have been described above, but the present invention is not limited to the above-mentioned embodiments and can be implemented in various other ways. For example, the above-mentioned embodiments can also be modified as follows to implement the present invention. It should be noted that the above-mentioned embodiments and the following modifications can also be combined respectively. The scheme composed of the constituent elements of the above-mentioned embodiments and the modifications is also included in the present invention. In addition, those skilled in the art can easily derive further effects and modifications. Therefore, the broader scheme of the present invention is not limited to the above-mentioned embodiments and modifications, and various changes can be made.

[0127] In the above-mentioned embodiment, as an electrical characteristic value such as a measured value, a target value, or a control object value, a current value may be used instead of a power value. In this case, for example, a reference function is defined as a relationship between current (I) and voltage (V), i.e., a VI characteristic. In addition, for example, the control unit 500a determines the target current Iref as a target value based on the measured value of the voltage measured by the sensor 100b, i.e., the voltage value Vo, and the reference function information, and performs feedback control in such a way that the difference between the target current Iref and the measured value Io of the current measured by the sensor 100b is below the allowable range, which is also called droopI control and is executed instead of droopP control. When the power control device 51 simulates droopI control, the vertical axis of the VI characteristic is voltage and the horizontal axis is current. When the control unit 500a simulates droopI control according to the reference function on the VI characteristic, the constant current mode is set as the control mode and outputs it to the power converter 11. When the received control mode is the constant current mode and the received target value is the current value I1 , the power converter 11 operates in the constant current mode and controls the output so that the electrical characteristic value of the bus 30 becomes the current value I1 .

[0128] In the above-mentioned embodiment, different reference function information and control area information may be stored in the storage unit 500b, and the reference function information and control area information used in controlling the power converter may be switched among the stored reference function information and control area information according to instructions from the EMS 40.

[0129] (Second embodiment)

[0130] Next, a second embodiment of the present invention will be described. It should be noted that in the following description, the same reference numerals are used for the same structures as those in the aforementioned embodiment, i.e., the first embodiment, and the description thereof is omitted, and the points different from the first embodiment are described. The power system 1 involved in the second embodiment includes a power control device 51A instead of the power control device 51. Fig.11 2 is a diagram showing a configuration of a power control device 51A. The power control device 51A is different from the power control device 51 in that the functional units are read out from the storage unit 500 b and implemented by the processor.

[0131] The control unit 500a includes a setting unit 500aa, an output unit 500ab, a determination unit 500ac, and a region setting unit 500ad as functional units implemented in software by executing a program. The determination unit 500ac determines the control method indicated by the control information transmitted from the EMS 40. The setting unit 500aa sets the control mode of the power converter 11 based on the determination result of the determination unit 500ac, the electrical characteristic value obtained from the power converter 11, the control region set by the region setting unit 500ad, and the like. In addition, the setting unit 500aa sets the target value of the output of the power converter 100a based on the determination result of the determination unit 500ac, the target value transmitted from the EMS 40, the set control region, and the electrical characteristic value received by the communication unit 500c. The output unit 500ab outputs the control mode and the target value set by the setting unit 500aa to the power converter 11. The region setting unit 500ad sets the control region that determines the control method of the power converter based on the reference function information stored in the storage unit 500b.

[0132] It should be noted that the other power control devices 52 to 55 may have the same configuration as the power control device 51A. However, the reference function information and target value transmitted from the EMS 40 to each power control device are different information depending on the connected power element.

[0133] <Centralized Control>

[0134] In the second embodiment, in the centralized control, the content of the update instruction output from the EMS 40 and obtained by the power control device 51A in step S207 is different. Specifically, the update instruction output from the EMS 40 to the power control device 51A includes control information, reference function information, and a target value of the output of the power conversion unit 100a. The control information is information that specifies the control method of the power conversion unit 100a, and is set by applying an optimization calculation. As a control method, for example, droopP control as an example of droop control, droopV control as an example of droop control, constant power control that controls the input and output power to be constant, constant voltage control that controls the input and output voltage to be constant, and constant current control that controls the input and output current to be constant are set by the EMS 40. In addition, the target value is a target value of the output of each power converter set by applying an optimization calculation.

[0135] <Local control>

[0136] Fig.12 51A is a flowchart showing the flow of processing performed by the control unit 500a of the power control device 51A in the local control. The control unit 500a executes, for example, Fig.12 First, the control unit 500a obtains the electric characteristic value received by the communication unit 500c from the power converter 11 (step S301). Next, the control unit 500a determines whether the control method indicated by the control information included in the update command output from the EMS 40 in step S207 is constant power control or constant current control (step S302).

[0137] When the control method indicated by the control information is constant power control or constant current control (yes in step S302), the control unit 500a sets the control mode to the constant power mode when the control method indicated by the control information is constant power control, and sets the control mode to the constant current mode when the control method indicated by the control information is constant current control, and sends the set control mode and the target value included in the update instruction obtained from the EMS 40 to the power converter 11 (step S307).

[0138] When the control method represented by the control information is not constant power control or constant current control (No in step S302), that is, when the control method represented by the control information is droopP control, droopV control or constant voltage control, the control unit 500a sets the control area based on the reference function information stored in the storage unit 500b (step S303). Fig.13A This is a diagram showing an example of a reference function represented by the reference function information transmitted from the EMS 40 and stored in the storage unit 500 b . Fig.13A The reference function represented by the curved line DL4 shown in FIG. 1 is formed by connecting a plurality of droop functions, namely lines DL41 to 45, which are defined according to the interval of the input value and have different droop characteristics. Fig.13A , the relationship between the power P and the voltage V on the bus 30 side of the power conversion unit 100a of the power converter 11, that is, the VP characteristic is shown, with the horizontal axis being P and the vertical axis being V. Line DL41 is a line connecting coordinates A (P1, V1) and coordinates B (P2, V2), line DL42 is a line connecting coordinates B (P2, V2) and coordinates C (P3, V3), line DL43 is a line connecting coordinates C (P3, V3) and coordinates D (P4, V4), line DL44 is a line connecting coordinates D (P4, V4) and coordinates E (P5, V5), and line DL45 is a line connecting coordinates E (P5, V5) and coordinates F (P6, V6). It should be noted that on line DL4, P1=P2, P3=P4, and P5=P6.

[0139] Fig. 13B 4 is a diagram showing an example in which the control unit 500a sets the lines DL41a to 45a as reference functions and the control region based on the line DL4. The control region is set to suppress disturbances in the bus 30 and to prevent the power converter 11 from operating at a low load.

[0140] exist Fig. 13B In the example shown, an area AR41 including line DL41a, an area AR42 including line DL42a, an area AR43 including line DL43a, an area AR44 including line DL44a, and an area AR45 including line DL45a are set. Fig. 13B In the example shown, a line DL41a including the line DL41, a line DL42a including a portion of the line DL42, a line DL43a including the line DL43, a line DL44a including a portion of the line DL44, and a line DL45a including the line DL45 are set.

[0141] Region AR41 is a region where the control mode is set to the constant power mode and the control point is placed on the line DL41a, and region AR45 is a region where the control mode is set to the constant power mode and the control point is placed on the line DL45a. Region AR42 is a region where the control mode is set to the constant voltage mode and the control point is placed on the line DL42a, and region AR44 is a region where the control mode is set to the constant voltage mode and the control point is placed on the line DL44a. Region AR43 is a region where the control mode is set to the stop mode. In order to prevent the power converter 11 from operating at a low load, the control unit 500a sets region AR43 to a region where the power converter 11 becomes a low load. Considering transient disturbances of the bus 30, control errors of the power converter 11, erroneous detection of electrical characteristic values ​​in the power converter 11, output errors of the power converter 11, and the like, a region where the voltage is above region AR43 and a region where the voltage is below region AR43 are set as regions where the control mode is the constant voltage mode.

[0142] In the area AR41, the maximum power value is P1+P a1 The minimum voltage value is V2-V a1 In the area of ​​area AR42, when the voltage value is higher than that in area AR43, the maximum power value is P3+P s When the voltage is lower than area AR43, the maximum power value is P3-P s In the area AR43, the maximum power value is P3+P s The minimum power value is P3-P s In addition, in the area AR43, the maximum voltage value is V3+Vs The minimum voltage value is V4-V s In the area of ​​area AR44, when the voltage value is lower than that in area AR43, the minimum power value is P3-P s In the area of ​​area AR45, the minimum power value is P6-P a2 , the maximum voltage value is V5+V a2 Here, P is set in consideration of the output error of the power converter 11 relative to the target value. a1 and P a2 .P s The setting is made so as to avoid the operation of the power converter 11 under low load. a1 、V a2 and V s The setting is made so that the control of the power converter 11 is stabilized.

[0143] Next, the control unit 500a sets the control mode of the power converter 11 (step S304) and sets the target value of the output of the power converter 11 (step S305). For example, when the operating point OP5 specified by the electrical characteristic value obtained from the power converter 11 moves from the line DL42 and Fig.14A or Fig. 14B When the operating point OP5 is located in the area AR42 as shown in FIG. Fig.14A or Fig. 14B In the case of the position shown in FIG. 5 , the control unit 500 a sets the voltage value at the position where a line drawn along the vertical axis from the operating point OP5 intersects the line DL42 as the target value of the constant voltage mode.

[0144] In addition, at the operating point OP5 specified by the obtained electrical characteristic value, Fig.15A When the vehicle is located in the area AR43 as shown, the control unit 500a sets the stop mode to the control mode.

[0145] In addition, when the operating point OP5 specified by the acquired electrical characteristic value moves from the area AR43 and Fig. 15B When the voltage moves to the area AR42 as shown in FIG. 1 , the control unit 500a sets the constant voltage mode as the control mode. Fig. 15B In the case of the position shown, the control unit 500a sets the voltage value at the position where the line DL42a is extended to the area AR43 and a line drawn along the vertical axis from the operating point OP5 intersects the extended line DL42a as the target value of the constant voltage mode.

[0146] In addition, at the operating point OP5 specified by the obtained electrical characteristic value, Fig.16A When the operating point OP5 is located in the area AR41 as shown in FIG. Fig.16A In the case of the position shown, the control unit 500a sets the power value at the position where a line drawn along the horizontal axis from the operating point OP5 intersects the line DL41 as the target value of the constant power mode.

[0147] In addition, the position of the action point OP5 is Fig. 16B In the case of the position shown in FIG. 1 , the control unit 500a sets the constant voltage mode as the control mode of the power converter 11. When the position of the operating point OP5 is Fig. 16B In the case of the position shown, the control unit 500a sets the voltage value at the position where the line DL42a is extended to the area AR41 and a line drawn along the vertical axis from the operating point OP5 intersects the extended line DL42a as the target value of the constant voltage mode.

[0148] The control unit 500a transmits the control mode set in step S304 and the target value set in step S305 to the power converter 11 (step S306). The power converter 11 receives the control mode and target value transmitted from the power control device 51A, and controls the output so that the electrical characteristic value becomes the target value based on the received control mode and target value, similarly to the above-mentioned embodiment.

[0149] It should be noted that the reference function and control area are not limited to Fig.13A and Fig. 13B As shown, in the case of other reference functions, the control area can also be set according to the reference function. Fig.17A This is an example of the reference function represented by the reference function information. Fig.17A The reference function represented by the line DL5 shown in FIG. 1 is formed by connecting a plurality of droop functions, namely, lines DL51 to DL55, which are defined according to the interval of the input value and have different droop characteristics. Fig.17A In the case of line DL5 shown, Fig. 17B As shown, the control unit 500a sets the lines DL51a to 55a and the areas AR51 to AR55 as reference functions based on the line DL5.

[0150] exist Fig. 17B In the example shown, an area AR51 including line DL51a, an area AR52 including line DL52a, an area AR53 including line DL53a, an area AR54 including line DL54a, and an area AR55 including line DL55a are set. Fig. 17BIn the example shown, a line DL51a including the line DL51, a line DL52a including a portion of the line DL52, a line DL53a on the V axis, a line DL54a including a portion of the line DL54, and a line DL55a including the line DL55 are set.

[0151] Area AR51 is an area where the control mode is set to the constant power mode and the operating point is controlled to be located on the line DL51a. Area AR55 is an area where the control mode is set to the constant power mode and the operating point is controlled to be located on the line DL55a. Area AR52 is an area where the control mode is set to the constant voltage mode and the operating point is controlled to be located on the line DL52a. Area AR54 is an area where the control mode is set to the constant voltage mode and the operating point is controlled to be located on the line DL54a. Area AR533 is an area where the control mode is set to the stop mode.

[0152] When the reference function is line DL5, in order to prevent the power converter 11 from operating at a low load, the control unit 500a sets the control mode to the stop mode in the area AR53 where the power converter 11 is in a low load region. It should be noted that when the minimum value of the power value in the area AR53 is -Ps, the maximum value of the power value in the area AR53 is set to 2Ps.

[0153] Fig.18A This is an example of the reference function represented by the reference function information. Fig.18A The reference function represented by the line DL6 shown in FIG. 1 is formed by connecting a plurality of droop functions, namely, lines DL61 to 65, which are defined according to the interval of the input value and have different droop characteristics. Fig.18A In the case of line DL6 shown in Fig.18B As shown, the control unit 500a sets the lines DL61a to DL65a and the areas AR61 to AR65 as reference functions based on the line DL6.

[0154] exist Fig.18B In the example shown, an area AR61 including line DL61a, an area AR62 including line DL62a, an area AR63 including line DL63a, an area AR64 including line DL64a, and an area AR65 including line DL65a are set. Fig.18B In the example shown, a line DL61a including the line DL61, a line DL62a including a portion of the line DL62, a line DL63a on the V axis, a line DL64a including a portion of the line DL64, and a line DL65a including the line DL65 are set.

[0155] Area AR61 is an area where the control mode is set to the constant power mode and the operating point is controlled to be located on the line DL61a. Area AR65 is an area where the control mode is set to the constant power mode and the operating point is controlled to be located on the line DL65a. Area AR62 is an area where the control mode is set to the constant voltage mode and the operating point is controlled to be located on the line DL62a. Area AR64 is an area where the control mode is set to the constant voltage mode and the operating point is controlled to be located on the line DL64a. Area AR63 is an area where the control mode is set to the stop mode.

[0156] When the reference function is line DL6, in order to prevent the power converter 11 from operating at a low load, the control unit 500a sets the control mode to the stop mode in the area AR63 where the power converter 11 is in a low load region. It should be noted that when the maximum value of the power value in the area AR63 is Ps, the minimum value of the power value in the area AR53 is set to -2Ps.

[0157] Fig.19A is an example of a reference function represented by the reference function information. The reference function represented by line DL7 shown in FIG19 is formed by connecting a plurality of droop functions defined according to the interval of the input value and having different droop characteristics, namely, line DL71, line DL72, and line DL75. For example, when the reference function is Fig.19A In the case of line DL7 shown in Fig.19B As shown, the control unit 500a sets the lines DL71a to DL75a and the areas AR71 to AR75 as reference functions based on the line DL7.

[0158] exist Fig.19B In the example shown, an area AR71 including line DL71a, an area AR72 including line DL72a, an area AR73 including line DL73a, an area AR74 including line DL74a, and an area AR75 including line DL75a are set. Fig.19B In the example shown, line DL71a including line DL71, line DL72a including part of line DL72, line DL63a provided on the V-axis, line DL74a including part of line DL72, and line DL75a including line DL75 are set.

[0159] Area AR71 is an area where the control mode is set to the constant power mode and the operating point is controlled to be located on the line DL71a. Area AR75 is an area where the control mode is set to the constant power mode and the operating point is controlled to be located on the line DL75a. Area AR72 is an area where the control mode is set to the constant voltage mode and the operating point is controlled to be located on the line DL72a. Area AR74 is an area where the control mode is set to the constant voltage mode and the operating point is controlled to be located on the line DL74a. Area AR73 is an area where the control mode is set to the stop mode.

[0160] When the reference function is line DL7, in order to prevent the power converter 11 from operating at a low load, the control unit 500a sets the line DL73a and the area AR73 for the area where the power converter 11 becomes a low load, and sets the control mode to the stop mode when the operating point is in the area AR73.

[0161] Fig. 20A This is an example of the reference function represented by the reference function information. Fig. 20A The reference function represented by the line DL8 shown in FIG. 8 is formed by connecting a plurality of droop functions, namely, lines DL81 to 83, which are defined according to the interval of the input value and have different droop characteristics. Fig. 20A In the case of line DL8 shown in Fig. 20B As shown, the control unit 500a sets the lines DL81a to 83a and the areas AR81 to AR83 as reference functions based on the line DL8.

[0162] exist Fig. 20B In the example shown, an area AR81 including the line DL81a, an area AR82 including the line DL82a, and an area AR83 including the line DL83a are set. Fig. 20B In the example shown, a line DL81 a provided on the V axis and including the line DL81 , a line DL82 a including a portion of the line DL82 , and a line DL83 a including the line DL83 are set.

[0163] Region AR83 is a region where the control mode is set to the constant power mode and the operating point is controlled to be on line DL83a. Region AR82 is a region where the control mode is set to the constant voltage mode and the operating point is controlled to be on line DL82a. Region AR81 is a region where the control mode is set to the stop mode.

[0164] When the reference function is line DL8 , control unit 500 a sets region AR81 to a region where the power value is negative and where power converter 11 operates at a low load, and sets the control mode to the stop mode when the operating point is in region AR81 .

[0165] Fig.21A This is an example of the reference function represented by the reference function information. Fig.21A The reference function represented by the line DL9 shown in FIG. 1 is formed by connecting a line DL91 representing constant power, a line DL92 representing constant voltage, a line DL93 representing constant power, a line DL94 representing constant voltage, and a line DL95 representing constant power, which are defined according to the interval of the input value. For example, when the reference function is Fig.21A In the case of line DL9 shown in FIG. Fig. 21B As shown, the control unit 500a sets the lines DL91a to DL95a and the areas AR91 to AR95 as reference functions based on the line DL9.

[0166] exist Fig. 21B In the example shown, an area AR91 including line DL91a, an area AR92 including line DL92a, an area AR93 including line DL93a, an area AR94 including line DL94a, and an area AR95 including line DL95a are set. Fig. 21B In the example shown, line DL91a including line DL91, line DL92a including part of line DL92, line DL93a including line DL93, line DL94a including part of line DL94, and line DL95a including line DL95 are set.

[0167] Area AR91 is an area where the control mode is set to the constant power mode and the operating point is controlled to be located on the line DL91a. Area AR95 is an area where the control mode is set to the constant power mode and the operating point is controlled to be located on the line DL95a. Area AR92 is an area where the control mode is set to the constant voltage mode and the operating point is controlled to be located on the line DL92a. Area AR94 is an area where the control mode is set to the constant voltage mode and the operating point is controlled to be located on the line DL94a. Area AR93 is an area where the control mode is set to the stop mode.

[0168] When the reference function is line DL9 , the control unit 500 a sets the control mode to the stop mode in a region AR93 where the power converter 11 is under a low load in order to prevent the power converter 11 from operating under a low load.

[0169] Fig.22A This is an example of the reference function represented by the reference function information. Fig.22A The reference function represented by the line DL10 shown in FIG. 1 is formed by connecting a line DL101 representing constant power, a line DL102 representing constant voltage, and a line DL105 representing constant power, which are defined according to the interval of the input value. Fig.22AIn the case of line DL10 shown in FIG. Fig. 22B As shown, the control unit 500 a sets the lines DL101 a to DL105 a and the areas AR101 to AR105 as reference functions based on the line DL10 .

[0170] exist Fig. 22B In the example shown, an area AR101 including line DL101a, an area AR102 including line DL102a, an area AR103 including line DL103a, an area AR104 including line DL104a, and an area AR105 including line DL105a are set. Fig. 22B In the example shown, a line DL101a including the line DL101, a line DL102a including a portion of the line DL102, a line DL103a provided on the V axis, a line DL104a including a portion of the line DL102, and a line DL105a including the line DL105 are set.

[0171] Area AR101 is an area where the control mode is set to the constant power mode and the operating point is controlled to be located on the line DL101a. Area AR105 is an area where the control mode is set to the constant power mode and the operating point is controlled to be located on the line DL105a. Area AR102 is an area where the control mode is set to the constant voltage mode and the operating point is controlled to be located on the line DL102a. Area AR104 is an area where the control mode is set to the constant voltage mode and the operating point is controlled to be located on the line DL104a. Area AR103 is an area where the control mode is set to the stop mode.

[0172] When the reference function is line DL10, in order to prevent the power converter 11 from operating at a low load, the control unit 500a sets the line DL103a and the area AR103 for the area where the power converter 11 becomes a low load, and sets the control mode to the stop mode when the operating point is in the area AR73.

[0173] It should be noted that, when the reference function is defined as the relationship between current (I) and voltage (V), that is, VI characteristics, regarding the control information, droopI control is set instead of droopV control, and constant current control is set instead of constant voltage control. When the control information indicates constant current control, the control unit 500a sets the control mode to the constant current mode, and sends the set control mode and the target value of the current included in the update instruction obtained from the EMS 40 to the power converter 11. In addition, when the reference function is defined as VI characteristics, the control unit 500a sets a control area in which the control mode is set to the constant power mode, a control area in which the control mode is set to the constant current mode, and a control area in which the control mode is set to the stop mode.

[0174] Industrial Applicability

[0175] The present invention can be utilized in a power control device, a power system, a control method of a power control device, and a control method of a central control device.

[0176] Description of Reference Numerals

[0177] 1 Power System

[0178] 11, 12, 13, 14, 15 Power converter

[0179] 21, 22, 23, 24, 25 Power elements

[0180] 30 Bus

[0181] 40 EMS

[0182] 41, 100c, 500a control unit

[0183] 42, 500b storage unit

[0184] 43, 100d, 500c Communications Department

[0185] 51, 52, 53, 54, 55 Power control device

[0186] 60 External Server

[0187] 100a Power conversion unit

[0188] 100b Sensor

[0189] 100ca Operation amount setting unit

[0190] 100cb Information Provider

[0191] 500aa Setting unit

[0192] 500ab Output

[0193] AR11, AR12, AR13, AR21, AR22, AR31, AR32 areas

[0194] DL1, DL2, DL3 lines

[0195] EV Electric Vehicle

[0196] NW Network

[0197] OP1, OP2, OP3, OP4 action points.

Claims

1. A power control device that controls a power converter that converts input power and outputs the power, wherein: The power control device comprises: a setting unit that sets the control mode of the power converter to any one of constant voltage control, constant current control, constant power control, and output stop in a manner corresponding to an input value, and sets a target value of the output of the power converter corresponding to the control mode based on the control mode and a reference function defined according to the input value; as well as An output unit outputs the control mode set by the setting unit and the target value set by the setting unit to the power converter.

2. The power control device according to claim 1, wherein: The setting unit sets the control mode based on a control region that defines a range of voltage, current, and power for performing constant voltage control, constant current control, constant power control, or output stop according to an input value in a manner corresponding to the reference function, The control region is set in such a manner as to suppress disturbance of the input value.

3. The power control device according to claim 2, wherein: The control region is defined so as to suppress a decrease in efficiency of the power converter.

4. The power control device according to claim 3, wherein: The setting unit sets the control mode to output stop to suppress a decrease in efficiency of the power converter.

5. The power control device according to claim 1, wherein: The power control device includes a communication unit that acquires control information indicating a control method of the power converter and a target value of an output of the power converter from an external device. When the control method indicated by the control information is constant power control or constant current control, the setting unit sets the control mode to the control method indicated by the control information, and the output unit outputs the target value obtained by the communication unit and the set control mode to the power converter.

6. The power control device according to claim 5, wherein: The power control device includes a region setting unit that sets a control region that specifies a range of voltage, current, and power for performing constant voltage control, constant current control, constant power control, or output stop according to an input value in a manner corresponding to the reference function. When the control method represented by the control information is constant voltage control, the setting unit sets the control mode specified by the control area corresponding to the target value and the target value determined according to the reference function, and the output unit outputs the set control mode and the target value to the power converter.

7. A power system, wherein: The power system comprises: The power control device according to any one of claims 1 to 6; as well as A power converter which obtains the control mode and the target value from the power control device, performs control corresponding to the acquired control mode based on the acquired target value when the acquired control mode is constant voltage control or constant power control, and stops output when the control mode is output stop.

8. A control method for a power control device, the power control device controlling a power converter that converts input power and outputs the power, wherein: The control method of the power control device comprises: a setting step of setting the control mode of the power converter to any one of constant voltage control, constant current control, constant power control, and output stop in a manner corresponding to an input value, and setting a target value of the output of the power converter corresponding to the control mode based on the control mode and a reference function defined according to the input value; as well as An output step of outputting the control mode set in the setting step and the target value set in the setting step to the power converter.

9. A control method of a central control device, the central control device controlling a power control device of a power converter that converts input power and outputs the power, wherein: The power control device comprises: a setting unit that sets the control mode of the power converter to any one of constant voltage control, constant current control, constant power control, and output stop in a manner corresponding to an input value, and sets a target value of the output of the power converter corresponding to the control mode based on the control mode and a reference function defined according to the input value; and an output unit that outputs the control mode set by the setting unit and the target value set by the setting unit to the power converter, The control method of the central control device includes a step of causing the central control device to output the reference function to the power control device.

Images