Processing device, program, and processing method

Abstract

To provide a processing device, etc. capable of efficiently controlling a value (passage current value) of passage current flowing through a DC distribution system.SOLUTION: A processing device is connected in a communicable manner with a storage battery unit disposed in a DC distribution system for distributing DC power obtained by converting AC power of an AC distribution system which is a power supply source. The processing device includes a processing unit that performs a process related to control of the storage battery unit. The processing unit acquires a value of passage current flowing through the DC distribution system, and changes output voltage from the storage battery unit according to the acquired passage current value and a predetermined upper limit current value.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a processing device, a program, and a processing method. [Background technology]

[0002] Power systems using DC voltage supply circuits are known (for example, see Patent Document 1). In the DC voltage supply circuit of Patent Document 1, an example of a power system is disclosed in which the ground fault detection circuit is provided between a DC power supply and a load. When a ground fault occurs at the positive end of the DC power supply, a ground fault current flows from the ground fault location to ground, and further flows from the ground through a ground point G and a ground fault detection relay. The ground fault detection circuit detects a ground fault using the current flowing through the ground fault detection relay. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-030099 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the power system disclosed in Patent Document 1, no consideration is given to efficiently controlling the value of the passing current (passing current value) flowing through the DC power distribution system.

[0005] The present invention has been made in consideration of the above circumstances, and its object is to provide a processing device, etc. that can efficiently control the value of the passing current (passing current value) flowing in a DC distribution system. [Means for solving the problem]

[0006] A processing device according to one embodiment of the present disclosure is a processing device that is communicatively connected to a storage battery unit arranged in a DC power distribution system that distributes DC power converted from AC power of an AC power distribution system, which is a power supply source, and includes a processing unit that performs processing related to the control of the storage battery unit, and the processing unit acquires a value of a passing current flowing in the DC power distribution system, and performs processing to change the output voltage from the storage battery unit in accordance with the acquired value of the passing current and a predetermined upper limit current value.

[0007] In this embodiment, the processing device (processing unit) performs processing for changing the output voltage of the storage battery unit arranged in the DC power distribution system. The processing for changing the output voltage includes, for example, processing for outputting a control signal (command value) to the storage battery unit. The storage battery unit changes the output voltage according to the control signal (command value) output from the processing device (processing unit). The DC power distribution system is connected to a branch end of a 6.6 kV high-voltage AC power distribution system such as a commercial AC system via a converter such as an AC / DC converter. The output voltage of the DC power distribution system is a low voltage of, for example, 750 V, and may be converted to a voltage lower than the output voltage of the high-voltage AC power distribution system. The output voltage of the DC power distribution system may be converted to a voltage equal to or higher than the output voltage of the high-voltage AC power distribution system. The converter connecting the high-voltage AC power distribution system and the low-voltage DC power distribution system may be a unidirectional AC / DC converter or a bidirectional C / DC converter. The processing unit of the processing device constantly monitors the passing current (distribution line passing current) in the distribution line of the DC distribution system by periodically or steadily acquiring the value of the passing current (passing current value) flowing through the DC distribution system from a current sensor arranged in the DC distribution system. The processing unit of the processing device acquires the upper limit current value, for example, by referring to an upper limit current value stored in advance in a memory unit of the processing device, based on information input from an external device connected in a communicable manner, or based on a calculation result using information obtained from various sensors. The processing unit of the processing device changes the output voltage from the storage battery unit based on the value (passing current value) of the passing current (distribution line passing current) flowing through the DC distribution system (distribution line) and the upper limit current value determined according to the system specifications of the DC distribution system, etc., and therefore can efficiently perform feedback control so that the distribution line passing current is always approximately equal to or less than a certain value. This allows the current passing through the distribution line (distribution line current) to be kept generally below a certain level regardless of the load fluctuations of the consumers, thereby preventing a large voltage drop even at the maximum consumer load, and making it possible to transmit electricity over a relatively long distance compared to AC transmission without increasing the diameter of the electric wire. Therefore, for example, it is possible to provide a method of transmitting electricity more economically than high voltage AC transmission to small consumers located far from the main line who cannot receive electricity with low voltage AC transmission.

[0008] In one aspect of the processing device according to the present disclosure, the processing unit increases the output voltage from the storage battery unit when the value of the passing current is greater than the upper limit current value, and decreases the output voltage from the storage battery unit when the value of the passing current is less than the upper limit current value.

[0009] In this embodiment, the processing unit of the processing device compares the value of the passing current (passing current value) flowing through the DC power distribution system with the upper limit current value. When comparing the passing current value with the upper limit current value, the processing unit of the processing device is not limited to comparing the instantaneous values ​​of these current values, and may determine that the passing current value is greater than the upper limit current value when the period (time) during which the passing current value is greater than the upper limit current value is equal to or greater than a predetermined period, and may determine that the passing current value is smaller than the upper limit current value when the period (time) during which the passing current value is less than the upper limit current value is equal to or greater than a predetermined period. Alternatively, the processing unit of the processing device may determine that the passing current value is greater than the upper limit current value when the passing current value exceeds the upper limit current value and the time integral value of the difference (passing current value-upper limit current value) is equal to or greater than a predetermined value, and may determine that the passing current value is smaller than the upper limit current value when the passing current value falls below the upper limit current value and the time integral value of the difference (upper limit current value-passing current value) is equal to or greater than a predetermined value. When the processing unit of the processing device determines that the value of the passing current is greater than the upper limit current value, the processing unit of the processing device increases the output voltage from the storage battery unit to decrease the value of the passing current (passing current value). When the processing unit of the processing device determines that the value of the passing current is less than the upper limit current value, the processing unit of the processing device decreases the output voltage from the storage battery unit to increase the value of the passing current (passing current value). When increasing or decreasing the output voltage from the storage battery unit, the processing unit of the processing device may change (increase or decrease) the output voltage in steps of, for example, 1V. This allows feedback control so that the value of the passing current (passing current value) approaches the upper limit current value, and allows equalization control so that the passing current value is approximately the upper limit current value. By performing such control, the storage battery charges and discharges to absorb the difference between the load current of the consumer and the upper limit current, and the value (passing current value) of the current flowing in the distribution line of the DC power distribution system (distribution line passing current) can be kept below the upper limit current value.In other words, even if a consumer to which power is supplied via a DC power distribution system experiences fluctuations in power consumption (load fluctuations) and the load current flowing from the DC power distribution system to the consumer fluctuates, the storage battery unit can function as a power buffer device, making it possible to roughly equalize the value of the passing current (passing current value) in the DC power distribution system due to conversion from the AC power distribution system.

[0010] In one embodiment of the processing device according to the present disclosure, when the value of the passing current is smaller than the upper limit current value, the processing unit charges the storage battery included in the storage battery unit with the passing current by lowering the output voltage from the storage battery unit, and when the charging rate of the storage battery becomes equal to or greater than a predetermined value, the charging of the storage battery is stopped.

[0011] In this embodiment, when the value of the passing current is smaller than the upper limit current value, the processing unit of the processing device reduces the output voltage from the storage battery unit, thereby charging the storage battery included in the storage battery unit with the passing current. The value of the passing current being smaller than the upper limit current value means that there is a surplus of the upper limit current value with respect to the load current flowing from the DC power distribution system to the consumer. In other words, the value of the load current (load current value) is in a state smaller than the upper limit current value. In this case, the processing unit of the processing device reduces the output voltage from the storage battery unit, increases the value of the passing current (passing current value) to approach the upper limit current value, and charges the storage battery using the surplus of the passing current (passing current close to the upper limit current value) with respect to the load current. In other words, during a period in which the value of the load current (load current value) by the consumer is smaller than the upper limit current value, the value of the passing current (passing current value) can be roughly uniformed and the storage battery can be charged. Then, the processing unit of the processing device periodically or constantly acquires charging state information including information on the remaining charge (remaining charge capacity, charging rate) of the storage battery, such as SOC (State of Charge: SOC (%) = remaining capacity (Ah) / full charge capacity (Ah) × 100) from the storage battery unit. The processing unit of the processing device stops charging the storage battery when the charging rate (SOC) of the storage battery becomes equal to or exceeds a predetermined value, such as 95% (when the predetermined value is reached). The processing unit of the processing device may, for example, increase the output voltage from the storage battery unit and make the output voltage from the storage battery unit and the output voltage of the DC power distribution system equal to each other, thereby reducing the current flowing from the DC power distribution system to zero. Alternatively, the processing unit of the processing device may stop the control over the storage battery unit to stop charging the storage battery. By performing such control, overcharging of the storage battery can be suppressed.

[0012] In one embodiment of the processing device according to the present disclosure, the storage battery unit includes a storage battery and a DCDC converter connected to the storage battery, and the processing unit changes the output voltage from the storage battery unit by operating the DCDC converter in a constant voltage control mode.

[0013] In this embodiment, the storage battery unit includes a storage battery such as a lithium ion battery or an all-solid-state battery, a DCDC converter connected in series to the storage battery, and a control device (such as a microcomputer) having a communication function for communicating with a processing device. The DCDC converter of the storage battery unit is configured to operate in a constant voltage control mode and to be able to change the output voltage according to a command from a separately provided processing device (controller). The processing unit of the processing device operates the DCDC converter in the constant voltage control mode to change the output voltage from the storage battery unit, thereby enabling efficient control of the storage battery unit.

[0014] In a processing device according to one embodiment of the present disclosure, a DCAC converter is connected to a service line connecting the DCDC converter and a distribution line of the DC distribution system, and the AC current converted by the DCAC converter corresponds to the load current to the consumer carried by the storage battery unit.

[0015] In this embodiment, the service line connecting the CDC converter and the distribution line of the DC power distribution system is branched, and the branched service line (branch line) is connected to the DCAC converter. Therefore, the total current of the passing current flowing through the service line branched from the distribution line of the DC power distribution system and the discharge current from the storage battery unit (storage battery) during discharge flows as a load current (when discharging: load current = passing current + discharge current) in the DCAC converter. When the storage battery unit (storage battery) is charging, a current obtained by subtracting the charging current flowing through the storage battery unit (storage battery) during charging from the passing current flowing through the service line branched from the distribution line of the DC power distribution system flows to the DCAC converter as a load current (when charging: load current = passing current - charging current). The DCAC converter converts the input direct current into alternating current and supplies alternating current power to loads such as electrical appliances of each consumer. In other words, the alternating current converted by the DCAC converter corresponds to the load current to the consumer borne by the storage battery unit. Consumers (AC power receiving consumers) supplied with AC power from these DCAC converters correspond to consumers that are handled by the storage battery units connected to the DCAC converters (handling the excess or shortage of power from the DC power distribution system). While it is assumed that a typical consumer load receives AC power (AC power), by converting DC power from the low-voltage DC power distribution system and the storage battery units to AC power by the DCAC converter, power can be efficiently supplied to the AC power receiving consumer. Note that the consumer load is not limited to AC power receiving (AC power receiving), and may be DC power receiving (DC power receiving).

[0016] In one embodiment of the processing device according to the present disclosure, the processing unit acquires the value of the passing current flowing through the service line, and changes the output voltage from the storage battery unit in accordance with the value of the passing current flowing through the service line and the predetermined upper limit current value, and the upper limit current value is set in accordance with the current value flowing through the storage battery connected to the service line and the load current to the consumer.

[0017] In this embodiment, a current sensor for detecting the value of the passing current (passing current value) is disposed in each of the service lines branched from the distribution line of the DC power distribution system. The current sensor detects the value of the passing current (passing current value) flowing through the service line and outputs it to the processing device. At this time, the upper limit current value is set based on a total current corresponding to the current value flowing through the storage battery connected to the service line and the load current to the consumer, and the processing unit of the processing device changes the output voltage from the storage battery unit according to the value of the passing current flowing through the service line and the upper limit current value thus set. In this way, the value of the passing current (passing current value) flowing through the service line is feedback-controlled so as to approach the upper limit current value corresponding to the load current to the consumer connected to the service line, and the passing current value can be uniformly controlled so as to be approximately the upper limit current value.

[0018] In the processing device according to one aspect of the present disclosure, the processing unit receives a command to change the upper limit current value, and changes the upper limit current value in response to the received command to change the upper limit current value.

[0019] In this aspect, the processing unit of the processing device receives a change command (a command to change the upper limit current value) input from an external device via an input device provided in the processing device or wireless communication, and stores the change command in, for example, a storage unit. The processing unit of the processing device changes the upper limit current value in response to the change command. The processing unit of the processing device may comprehensively determine the upper limit current value including the storage battery capacity and the distribution line equipment capacity. Alternatively, the processing unit of the processing device may determine the upper limit current value based on the daily average value of the load current in the consumer served by the storage battery unit. In this case, the capacity of the storage battery (storage battery capacity) may be a capacity that can correspond to the maximum value of the time integral of the difference (load current value - upper limit current value) between the load current value and the upper limit current value. Furthermore, the upper limit current value may be determined so that all devices connected to the DC power distribution system are within the operating range for the voltage drop that occurs when a passing current flows at the upper limit current value. In this way, the processing unit of the processing device changes the upper limit current value in response to the received change command, and therefore can change the output voltage of the storage battery unit based on the upper limit current value corresponding to the load current value (corresponding to the power consumption situation) to the consumer served by the storage battery unit.

[0020] A program according to one embodiment of the present disclosure causes a computer that is communicatively connected to a storage battery unit arranged in a DC distribution system that is converted to a lower voltage than the output voltage of an AC distribution system, which is a power supply source, to execute a process to acquire a value of a passing current flowing in the DC distribution system, and to perform a process to change the output voltage from the storage battery unit in accordance with the acquired value of the passing current and a predetermined upper limit current value.

[0021] In this aspect, it is possible to provide a program that causes a computer to function as a processing device that efficiently controls the value of the passing current (passing current value) flowing through a DC power distribution system.

[0022] A processing method according to one aspect of the present disclosure causes a computer that is communicatively connected to a storage battery unit arranged in a DC power distribution system that is converted to a lower voltage than the output voltage of an AC power distribution system, which is a power supply source, to execute a process that acquires a value of a passing current flowing through the DC power distribution system, and performs a process to change the output voltage from the storage battery unit according to the acquired value of the passing current and a predetermined upper limit current value.

[0023] In this aspect, it is possible to provide a processing method for making a computer function as a processing device that efficiently controls the value of a passing current (passing current value) flowing through a DC power distribution system. Effect of the Invention

[0024] It is possible to provide a processing device or the like capable of efficiently controlling the value of a passing current (passing current value) flowing through a DC power distribution system. [Brief description of the drawings]

[0025] [Figure 1] 1 is a system configuration diagram showing a configuration example of a DC power distribution system including a processing device according to a first embodiment. [Diagram 2] FIG. 2 is a block diagram showing a configuration example of a processing device and the like. [Diagram 3] 10 is a flowchart showing a processing procedure of a processing unit of the processing device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] (Embodiment 1) Hereinafter, an embodiment will be described with reference to the drawings. Fig. 1 is a system configuration diagram showing a configuration example of a DC power distribution system S including a processing device 1 according to the first embodiment. Fig. 2 is a block diagram showing a configuration example of the processing device 1 and the like. The DC power distribution system S includes a DC power distribution system S1 including a distribution line S10 and a plurality of service lines S11 branched off from the distribution line S10, and a processing device 1 and a storage battery unit 2 connected to each of these service lines S11. The DC power distribution system S1 is connected to a branch end (an end of a branch line branched off from a trunk line) of a 6.6 kV high voltage AC power distribution system K such as a commercial AC system, for example, via a converter K1.

[0027] The converter K1 is configured with a unidirectional AC / DC converter or a bidirectional AC / DC converter, and converts, for example, high voltage AC of 6.6 kV into low voltage DC of 750 V. Therefore, the DC distribution system S1 is configured as a low voltage DC distribution system S1 (low voltage DC distribution system S1). When there is no reverse power to the system (power transmission from the DC distribution system S1 to the high voltage AC distribution system K), the converter K1 may be configured with a unidirectional AC / DC converter, and when there is reverse power, the converter K1 may be configured with a bidirectional AC / DC converter.

[0028] The distribution line S10 of the DC distribution system S1 is extended toward an area (where the consumer U resides) that is relatively far away from the branch end of the high-voltage AC distribution system K. Although details will be described later, the passing current flowing through the distribution line S10 of the DC distribution system S1 is equalized and controlled to a predetermined upper limit current value. Therefore, by suppressing the voltage drop that occurs when the passing current flows at the upper limit current value, it is possible to transmit electricity over a relatively long distance.

[0029] A distribution line S10 of the DC distribution system S1 is provided with a plurality of (two in this embodiment) service lines S11 branching off from the distribution line S10. A processing device 1, a storage battery unit 2, and a DCAC converter 3 are disposed on each service line S11. The processing device 1, the storage battery unit 2, and the DCAC converter 3 constitute a DC distribution unit for supplying power supplied from the DC distribution system S1 to a consumer U.

[0030] The service line S11 of the DC distribution system S1 and the consumer U are connected by the DCAC converter 3 and an AC distribution network through which AC-converted low-voltage AC current (such as 210V) flows. When the distance between the DCAC converter 3 and the consumer U is relatively long, the DCAC converter 3 may convert the AC current (such as 6.6kV) and transmit the power. When the distance between the DCAC converter 3 and the consumer U is relatively short, the DCAC converter 3 may transmit the power at low-voltage AC (such as 210V). In this embodiment, the consumer U is assumed to receive AC power (AC power), but is not limited thereto, and may receive DC power (DC power). In this case, instead of the DCAC converter 3, a regulator that converts a DC voltage of 750V to a DC voltage of 100 to 200V may be used.

[0031] The storage battery unit 2 includes a storage battery 22 and a DCDC converter 21 that outputs a DC voltage obtained by stepping up or down the DC voltage from the storage battery 22 to convert the output voltage, and functions as a DC voltage power source. The storage battery 22 and the DCDC converter 21 are connected in series. A branch line branched from the service line S11 is connected between the DCDC converter 21 arranged in the service line S11 and the service entrance of the service line S11, and a DCAC converter 3 is connected to the end of the branch line. The DCAC converter 3 is connected to an AC power distribution network that is extended to the main house served by the storage battery unit 2.

[0032] The multiple storage battery units 2 are distributed and arranged in multiple regions (regions where consumers reside). Each storage battery unit 2 functions to absorb the excess or shortage of power for each consumer connected via a DCAC converter 3, and serves the consumer. The storage battery unit 2 may also be capable of supplying power via a distribution line S10 to an electrical load connected to a service line S11 on which other storage battery units 2 are arranged.

[0033] The processing device 1 communicatively connected to the storage battery units 2 may function as a monitoring device that monitors the state of the storage battery units 2, derives an output voltage value, and outputs the output voltage value. The processing device 1 is communicatively connected to the storage battery units 2 by wire (communication line) or wirelessly, and acquires, from the storage battery units 2, charging state information relating to the charging state of the storage batteries 22 included in each storage battery unit 2 periodically, regularly, or steadily. The charging state information includes data indicating the remaining charge (SOC) of each storage battery 22.

[0034] The processing device 1 is further connected to a current sensor S12 arranged on a service line S11 to which a storage battery unit 2 controlled by the processing device 1 is connected so as to be able to communicate with the current sensor S12. The current sensor S12 arranged on the service line S11 periodically or steadily outputs data on the value (passing current value) of a current (passing current) flowing through the service line S11 to the processing device 1. The sensor (passing current value detection unit) that detects the value (passing current value) of the passing current flowing through the service line S11 is not limited to the current sensor S12, and may be a voltage sensor. The processing device 1 may calculate the value (passing current value) of the passing current flowing through the service line S11 by using the DC voltage in the service line S11 acquired from the voltage sensor. The current sensor S12 is not limited to being arranged on the service line S11, and may be arranged on the distribution line S10. The processing device 1 changes the output voltage from the storage battery unit 2 according to the passing current value acquired from the current sensor S12 and a predetermined upper limit current value.

[0035] The processing device 1 is a computer (information processing device) capable of various information processing and sending and receiving information, such as a server device, a personal computer, etc. The server device includes not only a single server device, but also a cloud server device or a virtual server device configured by multiple computers. The processing device 1 includes a processing unit 11, a storage unit 12, and a communication unit 13.

[0036] The processing unit 11 has an arithmetic processing device equipped with a timing function, such as one or more CPUs (Central Processing Units), MPUs (Micro-Processing Units), GPUs (Graphics Processing Units), etc., and functions as a control unit that performs various information processing, control processing, etc. by reading and executing a program P (program product) stored in the memory unit 12.

[0037] The storage unit 12 includes a volatile storage area such as a static random access memory (SRAM), a dynamic random access memory (DRAM), a flash memory, etc., and a non-volatile storage area such as an EEPROM or a hard disk. The storage unit 12 stores in advance a program P (program product) and data to be referenced during processing. The program P (program product) stored in the storage unit 12 may be a program P (program product) read from a recording medium M readable by the processing device 1. Alternatively, the program P (program product) may be downloaded from an external computer (not shown) connected to a communication network (not shown) and stored in the storage unit 12.

[0038] The communication unit 13 is a communication module or communication interface for communicating with each storage battery unit 2 by wired communication such as Ethernet (registered trademark) or wirelessly, and is, for example, a short-range wireless communication module such as Wi-Fi (registered trademark) or Bluetooth (registered trademark), or a wide-range wireless communication module such as 4G or 5G. The control unit communicates with each storage battery unit 2 via the communication unit 13, for example, through an external network such as the Internet, or a LAN. The control unit may be connected to the current sensor S12 via the communication unit 13, or, when the control unit is configured by a microcomputer or the like, may be connected to the current sensor S12 via an input / output I / F of the microcomputer.

[0039] The storage battery unit 2 includes a DCDC converter 21 and a storage battery 22, and may further include a control device 23 that controls the DCDC converter 21 and the storage battery 22. The storage battery 22 is formed of, for example, a secondary battery such as a lithium ion battery, or a supercapacitor (electric double layer capacitor). The DCDC converter 21 is a device that converts a DC current (DC voltage) into another DC current (DC voltage). The DCDC converter 21 converts the DC voltage output from the storage battery 22 into a DC voltage indicated by an output voltage setting value in response to a control signal (command value) from the processing device 1, and outputs the converted DC voltage. The output DC voltage becomes the output voltage from the storage battery unit 2.

[0040] The control device 23 may be configured with, for example, a microcomputer or the like and function as a power conditioner. The control device 23 functioning as a power conditioner in this manner includes a control unit (CPU), a storage unit, and a communication unit, similar to the processing device 1, and communicates with the processing device 1 via the communication unit.

[0041] The control device 23 measures the state of charge (SOC) of the storage battery 22 and transmits the measured state of charge (SOC) to the processing device 1. When measuring the state of charge (SOC) of the storage battery 22, the control device 23 may acquire an open circuit voltage (OCV) of the storage battery 22 and estimate the state of charge (SOC) based on the acquired open circuit voltage.

[0042] The control device 23 receives the output voltage setting value transmitted from the processing device 1, and generates a control signal for the DCDC converter 21 based on the output voltage setting value. The control signal for the DCDC converter 21 is composed of, for example, a PWM signal, and the control device 23 outputs the control signal to the DCDC converter 21 to cause the DCDC converter 21 to step up or step down the voltage. As a result, the storage battery unit 2 outputs a DC voltage according to the output voltage setting value transmitted from the processing device 1.

[0043] In this embodiment, the control device 23 (power conditioner) of the storage battery unit 2 and the processing device 1 are described as separate devices, but are not limited to this. The control device 23 (power conditioner) of the storage battery unit 2 and the processing device 1 are substantially integrated, and the processing device 1 may be included in the storage battery unit 2, for example, by being housed in the housing of the storage battery unit 2.

[0044] 3 is a flowchart showing the processing procedure of the processing unit 11 of the processing device 1. The processing device 1, for example, monitors the state of the storage battery unit 2, sets an output voltage value (output voltage set value), and outputs the output voltage set value, and always functions as a system monitoring device for each of the service lines S11 of the DC power distribution system S1. The processing device 1 may perform processing according to the following flowchart as part of processing related to the system monitoring.

[0045] The processing unit 11 of the processing device 1 acquires a passing current value detected by the current sensor S12 (S101). The processing unit 11 of the processing device 1 periodically or steadily acquires a value of a passing current (passing current value) flowing through the DC distribution system S1 from the current sensor S12 arranged in the DC distribution system S1, thereby constantly monitoring a passing current (distribution line S10 passing current) in the distribution line S10 of the DC distribution system S1. The processing unit 11 of the processing device 1 stores the passing current value acquired from the current sensor S12 in the storage unit 12 in association with the time of acquisition (the time of detection by the current sensor S12).

[0046] The processing unit 11 of the processing device 1 determines whether the passing current value is equal to the upper limit current value (S102). The upper limit current value that is set in advance is stored in the memory unit 12 of the processing device 1. The processing unit 11 of the processing device 1 acquires the upper limit current value by referring to the memory unit 12.

[0047] The upper limit current value is set, for example, based on the daily average value of the load current in the consumer U served by the storage battery unit 2. Furthermore, the upper limit current value may be determined so that all devices connected to the DC power distribution system S1 are within the operating range for the voltage drop that occurs when the through current flows at the upper limit current value. The voltage drop is determined according to the line impedance of the distribution line S10 in the DC power distribution system S1 and the magnitude of the upper limit current value. Therefore, from the viewpoint of suppressing the voltage drop, it is preferable that the upper limit current value is small, and the upper limit current value may be determined based on the capacity of the storage battery unit 2 (storage battery 22) and the daily average value, the daily median value, the daily maximum value, or a combination thereof, of the load current in the consumer U served by the storage battery unit 2. By using the upper limit current value determined in this way, it is possible to operate the DC power distribution system S so that all devices connected to the DC power distribution system S1 are within the operating range for the voltage drop that occurs when the through current flows at the upper limit current value.

[0048] The processing unit 11 of the processing device 1 may, for example, acquire data relating to a daytime transition of a load current in a consumer U served by a storage battery unit 2 communicatively connected to the processing device 1 a plurality of times in a predetermined period, and calculate (derive) the upper limit current value by aggregating and analyzing the acquired data group. Alternatively, the processing unit 11 of the processing device 1 may, for example, receive a command relating to the upper limit current value (a command to set or change the upper limit current value) transmitted from an external device such as a monitoring device that monitors the entire DC power distribution system S, and set or change the upper limit current value based on the received command.

[0049] When determining whether the passing current value and the upper limit current value are identical, the processing unit 11 of the processing device 1 is not limited to determining that the passing current value and the upper limit current value are identical only when they are completely identical, but may determine that the passing current value and the upper limit current value are identical when the passing current value falls within a predetermined range based on the upper limit current value (for example, ±n%, where n can be set from 0.1 to 10). In other words, by setting the predetermined range based on the upper limit current value as a dead band, it is possible to suppress excessive voltage changes in the storage battery unit 2, i.e., hunting.

[0050] If the passing current value is equal to the upper limit current value (S102: YES), the processing unit 11 of the processing device 1 performs a loop process to execute the process of S101 again. As a result, the processing unit 11 of the processing device 1 periodically or steadily continues the process of acquiring the passing current value detected by the current sensor S12. When the passing current value becomes equal to the upper limit current value, the value of the passing current (passing current value) in the DC distribution system S1 is maintained (continued) in a state in which it is roughly uniform. As a result, in the low-voltage DC distribution system S1, it is possible to suppress voltage drop and transmit power over long distances.

[0051] If the passing current value is not equal to the upper limit current value (S102: NO), the processing unit 11 of the processing device 1 judges whether or not the passing current value is greater than the upper limit current value (S103). If the passing current value is not equal to the upper limit current value, for example, when the passing current value deviates from a dead zone that is substantially the same range as the upper limit current value, the processing unit 11 of the processing device 1 judges whether or not the passing current value is greater than the upper limit current value.

[0052] If the passing current value is greater than the upper limit current value (S103: YES), the processing unit 11 of the processing device 1 increases the output voltage of the storage battery unit 2 (S104). If the passing current value is greater than the upper limit current value, the processing unit 11 of the processing device 1 outputs a voltage increase command to the DCDC converter 21 of the storage battery unit 2 to increase the conversion ratio of the DCDC converter 21 and increase the output voltage of the storage battery unit 2. This starts discharging from the storage battery 22. The passing current value decreases due to the discharging of the storage battery 22, and can be made to move to approximate the upper limit current value. A total current obtained by adding up the discharge current flowing from the storage battery 22 that has started discharging and the passing current that has moved (decreased) to approximate the upper limit current value flows into the DCAC converter 3 that is branched off from the service line S11 and connected. The total current corresponds to a load current flowing to the consumer U connected via the DCAC converter 3. In this way, even if the value of the load current (load current value) flowing to the consumer U is greater than the upper limit current value, the discharge current from the storage battery unit 2 can be controlled to be uniform so that the passing current value is approximately the upper limit current value by compensating for the shortfall of the upper limit current value relative to the load current value.

[0053] If the passing current value is not greater than the upper limit current value (S103: NO), that is, if the passing current value is smaller than the upper limit current value, the processing unit 11 of the processing device 1 reduces the output voltage of the storage battery unit 2 (S1031). If the passing current value is smaller than the upper limit current value, the processing unit 11 of the processing device 1 outputs a voltage reduction command to the DCDC converter 21 of the storage battery unit 2, thereby reducing the conversion ratio of the DCDC converter 21 and reducing the output voltage by the storage battery unit 2. This starts charging the storage battery 22. The passing current value increases as the storage battery 22 is charged, and can be made to move to approximate the upper limit current value. A current obtained by subtracting the charging current flowing through the storage battery 22 that has started charging from the passing current that has moved (increased) to approximate the upper limit current value flows through the DCAC converter 3 that is branched off from the service line S11 and connected. The current thus subtracted corresponds to the load current flowing through the consumer U connected via the DCAC converter 3. In this way, even if the value of the load current (load current value) flowing to the consumer U is smaller than the upper limit current value, the charging current flowing to the storage battery unit 2 can be controlled to be uniform so that the passing current value is approximately the upper limit current value by absorbing the surplus of the upper limit current value relative to the load current value.

[0054] The processing unit 11 of the processing device 1 acquires the state of charge (SOC) of the storage battery 22 from the storage battery unit 2 (S1032). The control device 23 such as a power conditioner included in the storage battery unit 2 acquires the state of charge (SOC) of the storage battery 22 controlled by the control device 23, and performs processing to transmit data indicating the acquired state of charge (SOC) to the processing device 1 periodically or periodically. Alternatively, the processing device 1 may include the function of the control device 23 such as a power conditioner and be substantially included in the storage battery unit 2. The processing unit 11 of the processing device 1 acquires data indicating the state of charge (SOC) transmitted from the control device 23 of the storage battery unit 2, and stores the acquired data indicating the state of charge (SOC) in the storage unit 12 in association with a unit number or the like that uniquely identifies the storage battery unit 2 that is the transmission source and the acquisition time.

[0055] The processing unit 11 of the processing device 1 judges whether the remaining charge of the storage battery 22 is equal to or greater than a predetermined amount (S1033). The predetermined amount used for this judgment is stored in advance in the storage unit 12 as, for example, 95%, and the processing unit 11 of the processing device 1 acquires the predetermined amount by referring to the storage unit 12. The processing unit 11 of the processing device 1 compares the predetermined amount (remaining charge threshold) determined in advance according to the battery characteristics of the storage battery 22 with the current remaining charge (SOC) acquired from the storage battery unit 2, and judges whether the remaining charge of the storage battery 22 is equal to or greater than the predetermined amount.

[0056] If it is equal to or greater than the predetermined amount (S1033: YES), the processing unit 11 of the processing device 1 stops charging the storage battery 22 (S1034). If the remaining charge of the storage battery 22 is equal to or greater than the predetermined amount, that is, if the current state of charge (SOC) exceeds a threshold value of the remaining charge set as the predetermined amount, there is a concern that further charging may result in overcharging the storage battery 22, so the processing unit 11 of the processing device 1 stops charging the storage battery 22. When stopping the charging of the storage battery 22, the processing unit 11 of the processing device 1 may, for example, increase the output voltage from the storage battery unit 2 to make the output voltage from the storage battery unit 2 equal to the output voltage of the DC distribution system S1 (the voltage at the service line S11), thereby making the current flowing from the DC distribution system S1 to the storage battery 22 zero. Alternatively, the processing unit 11 of the processing device 1 may stop the charging of the storage battery 22 by stopping the control of the DCDC converter 21 of the storage battery unit 2. Alternatively, the processing unit 11 of the processing device 1 may stop charging the storage battery 22 by turning off a relay connecting the storage battery unit 2 and the service line S11 of the DC power distribution system S1.

[0057] If the amount is not equal to or greater than the predetermined amount (S1033: NO), after execution of process S1034 or after execution of process S104, the processing unit 11 of the processing device 1 performs loop processing to execute the processes from S101 again. By performing loop processing in this manner, the processing unit 11 of the processing device 1 continuously performs feedback control so that the value of the passing current flowing through the service line S11 (passing current value) approaches an upper limit current value corresponding to the load current to the consumer U connected to the service line S11, and can perform equalization control so that the passing current value becomes approximately the upper limit current value.

[0058] The embodiments disclosed herein are illustrative in all respects and should not be considered as limiting. The scope of the present invention is defined by the claims, not by the above meaning, and is intended to include all modifications within the scope and meaning equivalent to the claims.

[0059] The claims may be combined with each other regardless of the form of reference. The claims include multiple dependent claims that depend on multiple dependent claims. The claims do not include multiple dependent claims that depend on a multiple dependent claim, but multiple dependent claims that depend on a multiple dependent claim may be included. [Explanation of symbols]

[0060] K high voltage AC power distribution system, K1 converter, S DC power distribution system, S1 DC power distribution system, S10 power distribution line, S11 service line, S12 current sensor, 1 processing device, 11 processing unit, 12 storage unit, M recording medium, P program, 13 communication unit, 2 storage battery unit, 21 DCDC converter, 22 storage battery, 23 control device, 3 DCAC converter, U consumer

Claims

1. A processing device communicably connected to a storage battery unit arranged in a DC power distribution system that distributes DC power obtained by converting AC power from an AC power distribution system that is a power supply source, a processing unit that performs processing related to control of the storage battery unit; The processing unit includes: Obtaining a value of a passing current flowing through the DC power distribution system; A process for changing an output voltage from the storage battery unit is performed according to the acquired value of the passing current and a predetermined upper limit current value. Processing unit.

2. The processing unit includes: When the value of the passing current is greater than the upper limit current value, increasing the output voltage from the storage battery unit; When the value of the passing current is smaller than the upper limit current value, the output voltage from the storage battery unit is decreased. The processing device of claim 1 .

3. The processing unit includes: When the value of the passing current is smaller than the upper limit current value, an output voltage from the storage battery unit is decreased, thereby charging a storage battery included in the storage battery unit with the passing current; When the charging rate of the storage battery reaches or exceeds a predetermined value, charging of the storage battery is stopped. The processing device according to claim 2 .

4. The storage battery unit includes a storage battery and a DC-DC converter connected to the storage battery, The processing unit changes the output voltage from the storage battery unit by operating the DC-DC converter in a constant voltage control mode. The processing device of claim 1 .

5. A DC / AC converter is connected to a service line that connects the DC / DC converter and a distribution line of the DC distribution system, The AC current converted by the DC-AC converter corresponds to the load current to the consumer carried by the storage battery unit. The processing device according to claim 4 .

6. The processing unit includes: Obtaining a value of a passing current flowing through the drop line; changing an output voltage from the storage battery unit in accordance with a value of a passing current flowing through the service line and the predetermined upper limit current value; The upper limit current value is set according to a current value flowing through the storage battery connected to the service line and a load current to the consumer. The processing device according to claim 5 .

7. The processing unit includes: A command to change the upper limit current value is received; The upper limit current value is changed in response to the received change command. The processing device of claim 6.

8. A computer connected in a communicable manner to a storage battery unit arranged in a DC power distribution system that distributes DC power obtained by converting AC power from an AC power distribution system that is a power supply source, Obtaining a value of a passing current flowing through the DC power distribution system; A process for changing an output voltage from the storage battery unit is performed according to the acquired value of the passing current and a predetermined upper limit current value. A program that executes a process.

9. A computer connected in a communicable manner to a storage battery unit arranged in a DC power distribution system that distributes DC power obtained by converting AC power from an AC power distribution system that is a power supply source, Obtaining a value of a passing current flowing through the DC power distribution system; A process for changing an output voltage from the storage battery unit is performed according to the acquired value of the passing current and a predetermined upper limit current value. A processing method for causing a process to be performed.

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