DC Power System

Abstract

This DC power supply system (1) comprises: an electric vehicle (20); a storage battery (40); a solar power generation device (30); a rectifier (50) that converts AC current supplied from a commercial power supply (60) into DC current and supplies the DC current to a load; and a control device (10). The control device (10) determines a charge / discharge-related pattern from among charge patterns and discharge patterns on the basis of the presence / absence of surplus power in the solar power generation device (30) and current time information, determines one operation mode in the determined pattern on the basis of a comparison result between a charge state index of the electric vehicle (20) and a predetermined reference value and a comparison result between a charge state index of the storage battery (40) and a predetermined reference value, and performs charge / discharge-related control on the basis of the determined operation mode.

Description

[Technical field]

[0001] The present disclosure relates to a DC power supply system including an electric vehicle (hereinafter also referred to as "EV"), a storage battery (typically a lithium-ion battery (hereinafter also referred to as "LIB")), and a photovoltaic power generation device. Note that the photovoltaic power generation device will hereinafter also be referred to as "PV", which is derived from photovoltaic. [Background technology]

[0002] In recent years, there has been an increasing demand for communication infrastructure that can provide uninterrupted power even during disasters, in order to strengthen disaster resistance, and for example, backup power sources have been installed at base stations. The backup power sources mainly use lead-acid batteries, but because lead-acid batteries have a low energy density, it can be difficult to install more batteries due to space limitations at base stations.

[0003] Meanwhile, there has been growing expectation recently that the use of distributed power sources, including electric vehicles equipped with fuel cells, will improve resilience in the event of a disaster, and in the future, it will become necessary to establish technology for supplying power to base stations using electric vehicles as part of disaster prevention measures.

[0004] In addition, as the use of natural energy such as solar power generation is gaining attention, solar power generation devices are increasingly being installed in base stations. Currently, most DC power generated by solar power generation devices is converted to AC by a power conditioner and used. In this case, during a power outage due to a disaster or the like, the power conditioner does not operate, and the DC power generated by the solar power generation device is not supplied to the communication device in the base station. Therefore, from the viewpoint of securing power sources during disasters, etc., DC power supply systems are gaining attention in order to enable the DC power generated by the solar power generation device to be supplied to the communication device even during a power outage. For example, Patent Document 1 discloses a DC power supply system in which a total of four DC power sources, including a rectifier (also called a system power source) that converts AC power from a commercial power system into DC power, a solar power generation device, a storage battery, and an electric vehicle, are connected to a communication load. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6577076 Summary of the Invention [Problem to be solved by the invention]

[0006] In a DC power supply system in which the four DC power sources described above are connected to a communication load, it is necessary to maintain a certain level of State Of Charge (hereinafter also referred to as "SOC"), which is an index showing the state of charge of an electric vehicle, in consideration of the fact that the electric vehicle will be used (moved) as a vehicle. In addition, it is also necessary to maintain a certain level of SOC for the storage battery as well, in order to provide backup in the event of a power outage in the grid. Furthermore, in order to effectively utilize the surplus power generated by the solar power generation system, a control method is desired that effectively charges the storage battery and the electric vehicle with the surplus power generated.

[0007] The present disclosure has been made to solve the above-mentioned problems, and aims to effectively utilize surplus generated power from a solar power generation device while ensuring the charge state required for the movement of an electric vehicle and the charge state of a storage battery required for backup function. [Means for solving the problem]

[0008] The DC power supply system of the present disclosure includes an electric vehicle, a storage battery, a solar power generation device, a rectifier that converts AC current supplied from a commercial power source into DC current and supplies the DC power to a load, and a control device that performs control related to charging and discharging, and the control device includes a pattern determination unit that determines a pattern related to charging and discharging from a charging pattern and a discharging pattern based on the presence or absence of surplus power in the solar power generation device and current time information, and an operation mode determination unit that determines one operation mode in the pattern determined by the pattern determination unit based on a comparison result of a charge state indicator of the electric vehicle with a predetermined reference value and a comparison result of a charge state indicator of the storage battery with a predetermined reference value, and performs control related to charging and discharging based on the determined operation mode.

[0009] In the above DC power supply system, a pattern related to charging and discharging is determined from a charging pattern and a discharging pattern based on the presence or absence of surplus power in the photovoltaic power generation device and current time information. Therefore, for example, a pattern related to charging and discharging can be appropriately determined depending on whether the current time is daytime when the photovoltaic power generation device can operate and the presence or absence of surplus power in the photovoltaic power generation device. Also, based on a comparison result between a charge state index of the electric vehicle and a reference value and a comparison result between a charge state index of the storage battery and a reference value, one operation mode in the determined pattern is determined, and control related to charging and discharging is performed based on the determined operation mode. Therefore, by monitoring the charge state of the electric vehicle and the charge state of the storage battery, a charge state necessary for the movement of the electric vehicle and a charge state of the storage battery necessary for the backup function are ensured, and control related to charging and discharging based on an appropriate operation mode is realized, and surplus generated power of the photovoltaic power generation device can be effectively utilized. Effect of the Invention

[0010] According to the present disclosure, it is possible to effectively utilize surplus generated power from a solar power generation device while ensuring the charge state required for the movement of an electric vehicle and the charge state of a storage battery required for a backup function. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a configuration diagram of a DC power supply system in first and second embodiments. [Diagram 2] FIG. 2 is a configuration diagram of a control device in the first and second embodiments. [Diagram 3] FIG. 2 is a functional block diagram showing a configuration of a control unit in the first embodiment. [Figure 4] 13A is a table showing examples of operation modes in a discharging pattern, and FIG. 13B is a table showing examples of operation modes in charging patterns 1 and 2. FIG. [Diagram 5] FIG. 4 is a flow chart showing a charge / discharge control process in the first embodiment. [Figure 6] FIG. 11 is a flow chart showing a process of determining an operation mode of a discharge pattern. [Figure 7] FIG. 11 is a flow chart showing an operation mode determination process for a charging pattern 1. [Figure 8] FIG. 11 is a functional block diagram showing a configuration of a control unit in a second embodiment. [Figure 9] FIG. 11 is a flow chart showing a charge / discharge control process in a second embodiment. [Figure 10] FIG. 13 is a flowchart showing an operation mode determination process for a charging pattern 2. [Figure 11] FIG. 2 is a diagram illustrating an example of a hardware configuration of a control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment according to the present disclosure will be described with reference to the drawings. In the following, a first embodiment relating to a basic type of charge / discharge control in a DC power supply system in which a total of four DC power sources, a system power source, a solar power generation device, a storage battery, and an electric vehicle, are connected to a communication load, and a second embodiment in which a process for adjusting the charging current to the electric vehicle depending on the situation is further added will be described in order.

[0013] [Overall configuration of DC power supply system] First, the overall configuration of the DC power supply system according to the first and second embodiments will be described.

[0014] 1, the DC power supply system 1 includes an electric vehicle 20, a storage battery 40, a solar power generation device 30, a rectifier 50 that converts AC current supplied from a commercial power supply 60 into DC current with a voltage of about 48 V and supplies the DC power, and a control device 10 that performs control related to charging and discharging, which will be described later. This DC power supply system 1 is provided in a base station or the like, and is configured such that a total of four DC power supplies, namely, a system power supply (rectifier 50 and commercial power supply 60), the solar power generation device 30, the storage battery 40, and the electric vehicle 20, are connected to a communication load (such as communication equipment in a base station) 70 via the control device 10.

[0015] As shown in FIG. 2, the control device 10 includes a control unit 11 that determines a charge / discharge pattern and an operating mode, which will be described later, and performs control related to charging and discharging in the DC power supply system 1, a charge / discharge switching unit 12 that switches between charging and discharging in accordance with the charge / discharge pattern determined by the control unit 11, a voltage sensor 13 that measures the voltage of the bus (hereinafter referred to as "bus voltage"), which is the power supply path from the rectifier 50 to the communication load 70, and a charge / discharge unit 14 that performs charging and discharging in accordance with the operating mode determined by the control unit 11.

[0016] [First embodiment] 3, the control unit 11 in the first embodiment includes a timer unit 11A, a bus voltage monitoring unit 11B, a pattern determination unit 11C, an operation mode determination unit 11D, a storage battery state monitoring unit 11E, and an EV state monitoring unit 11F. Among these, the timer unit 11A is a functional unit that provides current time information to the pattern determination unit 11C, and the bus voltage monitoring unit 11B is a functional unit that monitors the bus voltage measured and output by the voltage sensor 13 in FIG. 2, and provides the obtained bus voltage information to the pattern determination unit 11C.

[0017] The pattern determination unit 11C is a functional unit that determines a pattern related to charging and discharging from a charging pattern and a discharging pattern based on the presence or absence of surplus power in the photovoltaic power generation device 30 and current time information. Furthermore, the pattern determination unit 11C determines that there is surplus power in the photovoltaic power generation device 30 when the output voltage of the photovoltaic power generation device 30 exceeds a predetermined surplus power threshold. In practice, the presence or absence of surplus power is determined by utilizing the characteristic that the output voltage of the photovoltaic power generation device 30 becomes equal to the bus voltage when surplus power is generated, and by monitoring whether the bus voltage has exceeded the surplus power threshold at which it can be determined that there is surplus power. In this way, the presence or absence of surplus power can be appropriately determined by utilizing the characteristic that the output voltage of the photovoltaic power generation device 30 becomes equal to the bus voltage when surplus power is generated.

[0018] The pattern determination unit 11C defines a time period during which power generation by the solar power generation device 30 is expected (for example, a time period from sunrise to sunset) as a "daytime" and a time period other than the daytime as a "nighttime". Assuming that electricity rates tend to be higher during the daytime than during the nighttime, the pattern determination unit 11C aims to purchase electricity as cheaply as possible during the nighttime while making the most of renewable energy. Specifically, when the current time is daytime and it is determined that there is surplus power in the solar power generation device 30, and when the current time is nighttime, the pattern determination unit 11C determines a pattern related to charging and discharging as a charging pattern, and when the current time is daytime and it is determined that there is no surplus power in the solar power generation device 30, the pattern determination unit 11C determines a pattern related to charging and discharging as a discharging pattern. With this pattern determination method, it is possible to use electricity as cheaply as possible during the nighttime while making the most of renewable energy, even when using a system power source. Details of the above process will be described later with reference to Figs. 5 to 7.

[0019] The battery state monitoring unit 11E is a functional unit that monitors the SOC, which is a state-of-charge index indicating the state of charge of the storage battery 40, and provides the obtained SOC information of the storage battery 40 to the operation mode determination unit 11D. The EV state monitoring unit 11F is a functional unit that monitors the SOC, which is a state-of-charge index indicating the state of charge of the electric vehicle 20, and provides the obtained SOC information of the electric vehicle 20 to the operation mode determination unit 11D.

[0020] The operation mode determination unit 11D determines the SOC (SOC EV ) with a predetermined reference value, and the SOC (SOC LIB ) with a predetermined reference value, and based on the comparison results, determines one operation mode in the pattern determined by the pattern determination unit 11C. The details will be described later with reference to Figs. 6 and 7, but a number of reference values ​​are used as the above-mentioned predetermined reference value. For example, SOC EV For the SOC, the lower limit is set in advance. lim , the SOC, which is the alert level set higher than this lower limit low, and is compared with 100% (or a predetermined value close to 100%) to determine whether or not the battery is fully charged. low " is the SOC of electric vehicles 20 EV In the process of FIG. 6 described later, the SOC of the electric vehicle 20 is set to a threshold value. EV is the alert value SOC low If it is determined that the SOC is below 100%, the storage battery 40 is added to the electric vehicle 20 and the solar power generation device 30 as a power supply source to the communication load 70 (switching from operation mode 1 to 2, which will be described later), thereby relatively suppressing the power supply from the electric vehicle 20. LIB For the SOC, the lower limit is set in advance. LIBlim , and is compared with 100% (or a predetermined value close to 100%) to determine whether or not the battery is fully charged. The operation mode determination unit 11D also performs control related to charging and discharging based on the determined operation mode by sending control signals to the charge / discharge switching unit 12 and the charge / discharge unit 14 in FIG.

[0021] Here, various operation modes in the discharge pattern will be outlined with reference to Fig. 4(a). In the discharge pattern, "operation mode 1" is an operation mode in which power is supplied from the electric vehicle 20 and the solar power generation device 30 to the communication load 70, and "operation mode 2" is an operation mode in which power is supplied from the electric vehicle 20, the storage battery 40, and the solar power generation device 30 to the communication load 70. "Operation mode 3" is an operation mode in which power is supplied from the storage battery 40 and the solar power generation device 30 to the communication load 70, and "operation mode 0" is an operation mode in which power is supplied to the communication load 70 only from the system power supply (rectifier 50 and commercial power supply 60).

[0022] Next, various operation modes in the charging pattern will be outlined with reference to FIG. 4(b). In the charging pattern, "operation mode 4" is an operation mode in which power from the rectifier 50 or the solar power generation device 30 is supplied to the electric vehicle 20, the storage battery 40, and the communication load 70, and "operation mode 5" is an operation mode in which power from the rectifier 50 or the solar power generation device 30 is supplied to the electric vehicle 20 and the communication load 70. In addition, "operation mode 6" is an operation mode in which power from the rectifier 50 or the solar power generation device 30 is supplied to the storage battery 40 and the communication load 70, and "operation mode 7" is an operation mode in which power from the rectifier 50 or the solar power generation device 30 is supplied only to the communication load 70. In the above operation modes 4 to 7, power from the "solar power generation device 30" is supplied when surplus power is generated in the solar power generation device 30, and power from the "rectifier 50" is supplied otherwise.

[0023] [Charge / Discharge Control Process in the First Embodiment] The charge / discharge control process executed by the control unit 11 will be described with reference to Figs. 5 to 7. The pattern determination unit 11C basically determines the charge / discharge pattern to be the discharge pattern if the current time is in the "daytime zone", and to be the charge pattern 1 if the current time is in the "nighttime zone". However, if surplus power is generated in the solar power generation device 30 even during the "daytime zone", the charge / discharge pattern is switched from the discharge pattern to the charge pattern in order to make effective use of renewable energy. The process in Fig. 5 is executed repeatedly at, for example, a predetermined time interval. Therefore, the charge / discharge pattern is switched depending on the current time and whether or not there is surplus power in the solar power generation device 30, and the SOC (SOC EV ), SOC of storage battery 40 (SOC LIB ) changes, the operating mode also changes.

[0024] Specifically, as shown in Fig. 5, if the current time is "daytime" (YES in step S1), the pattern determination unit 11C causes the operation mode determination unit 11D to execute the operation mode determination process of Fig. 6 (step S2). EVis the predetermined lower limit SOC lim SOC is set higher than the threshold low If it exceeds (YES in step S21), operation mode 1 (an operation mode in which power from the electric vehicle 20 and the solar power generation device 30 is supplied to the communication load 70) is determined (step S22), and an operation is executed in which power from the electric vehicle 20 and the solar power generation device 30 is supplied to the communication load 70 based on the operation mode. Thereafter, the process of step S2 in Fig. 5 is repeatedly executed unless surplus power is generated in the solar power generation device 30 or the current time falls within the "nighttime hours".

[0025] In step S2 (processing of FIG. 6), the SOC of the electric vehicle 20 EV is the alert value SOC low If the result is NO in step S21, the lower limit SOC lim If it exceeds this limit (YES in step S23), operation mode 2 (an operation mode in which power is supplied from the storage battery 40, the electric vehicle 20, and the solar power generation device 30 to the communication load 70) is determined (step S24), and an operation is executed in which power is supplied from the storage battery 40, the electric vehicle 20, and the solar power generation device 30 to the communication load 70 based on this operation mode.

[0026] Then, the SOC of electric vehicles 20 EV SOC falls to the lower limit lim If the SOC of the storage battery 40 is below the threshold (NO in step S23), the discharge from the electric vehicle 20 is stopped and the electric vehicle 20 is put into a standby state. LIB is the lower limit SOC LIBlim While the SOC of the storage battery 40 is greater than the SOC of the storage battery 40 (YES in step S25), the operation mode 3 (an operation mode in which power from the storage battery 40 and the solar power generation device 30 is supplied to the communication load 70) is determined (step S26), and the operation of supplying power from the storage battery 40 and the solar power generation device 30 to the communication load 70 based on the operation mode is executed. LIB SOC falls to the lower limit LIBlim6, the SOC of the electric vehicle 20 is determined for the operation mode of the discharge pattern. EV and SOC of battery 40 LIB Depending on each latest value, an appropriate operating mode can be determined.

[0027] On the other hand, if it is determined during the loop of steps S1 to S3 in FIG. 5 that the bus voltage has exceeded the surplus power threshold and thus surplus power has been generated in the solar power generation device 30 (YES in step S3), an operation mode determination process for charging pattern 1 (FIG. 7) is executed in step S4 to switch from the discharging pattern to the charging pattern in order to make effective use of renewable energy.

[0028] In step S4 (the process of FIG. 7), the operation mode determination unit 11D determines whether the SOC of the storage battery 40 is LIB It is determined whether the storage battery 40 is in a fully charged state based on whether the SOC of the electric vehicle 20 has reached 100% (or a predetermined value close to 100%) (step S41). EV It is determined whether the electric vehicle 20 is in a fully charged state depending on whether the charge reaches 100% (or a predetermined value close to 100%) (steps S42, S45).

[0029] Here, if neither the storage battery 40 nor the electric vehicle 20 is fully charged (NO in step S41 and NO in S45), operation mode 4 (an operation mode in which power from the rectifier 50 or the solar power generation device 30 is supplied to the electric vehicle 20, the storage battery 40, and the communication load 70) is determined (step S47), and based on this operation mode, an operation is executed to supply power from the rectifier 50 or the solar power generation device 30 to the electric vehicle 20, the storage battery 40, and the communication load 70.

[0030] Furthermore, if the storage battery 40 is not fully charged but the electric vehicle 20 is fully charged (NO in step S41 and YES in S45), there is no need to charge the electric vehicle 20, so operation mode 6 (an operation mode in which power from the rectifier 50 or the solar power generation device 30 is supplied to the storage battery 40 and the communication load 70) is determined (step S46), and based on this operation mode, an operation is executed to supply power from the rectifier 50 or the solar power generation device 30 to the storage battery 40 and the communication load 70.

[0031] Furthermore, if the storage battery 40 is fully charged but the electric vehicle 20 is not fully charged (YES in step S41 and NO in S42), there is no need to charge the storage battery 40, so operation mode 5 (an operation mode in which power from the rectifier 50 or the solar power generation device 30 is supplied to the electric vehicle 20 and the communication load 70) is determined (step S44), and an operation is executed to supply power from the rectifier 50 or the solar power generation device 30 to the electric vehicle 20 and the communication load 70 based on this operation mode.

[0032] Furthermore, when both the storage battery 40 and the electric vehicle 20 are fully charged (YES in steps S41 and YES in S42), there is no need to charge the storage battery 40 and the electric vehicle 20, so operation mode 7 (an operation mode in which power from the rectifier 50 or the solar power generation device 30 is supplied only to the communication load 70) is determined (step S43), and an operation is executed in which power from the rectifier 50 or the solar power generation device 30 is supplied only to the communication load 70 based on this operation mode. By the process of Fig. 7, an appropriate operation mode can be determined for the operation mode of the charging pattern depending on whether the storage battery 40 is fully charged or not and whether the electric vehicle 20 is fully charged or not.

[0033] According to the first embodiment described above, a pattern related to charging and discharging is appropriately determined depending on whether the current time is daytime or not and whether there is surplus power in the solar power generation device 30, and the SOC of the electric vehicle 20 and the storage battery 40 are monitored to appropriately determine the operation mode. Therefore, while ensuring the charge state required for the movement of the electric vehicle 20 and the charge state of the storage battery 40 required for the backup function, control related to charging and discharging based on an appropriate operation mode is realized, and the surplus generated power of the solar power generation device 30 is distributed to the storage battery 40 and the electric vehicle 20 for charging, thereby making the most of renewable energy and realizing a stable supply of power to the communication load 70 (for example, communication equipment in a base station, etc.), thereby contributing to improving the disaster resistance of the base station. In addition, it is possible to achieve cost reduction by reducing the number of discharge circuits through discharge control based on DC voltage control.

[0034] [Second embodiment] Next, as a second embodiment, an embodiment in which a process for adjusting the charging current to the electric vehicle depending on the situation is further added will be described.

[0035] As shown in FIG. 8, the control unit 11 in the second embodiment includes a timer unit 11A, a bus voltage monitoring unit 11B, a pattern determination unit 11C, an operation mode determination unit 11D, a storage battery state monitoring unit 11E, and an EV state monitoring unit 11F, similar to the control unit 11 in the first embodiment (FIG. 3). However, it differs from the first embodiment in that the operation mode determination unit 11D includes a charging current adjustment unit 11H and a charging control unit 11G, which will be described below.

[0036] When the solar power generation device 30 generates surplus power and neither the storage battery 40 nor the electric vehicle 20 is fully charged, the charging current adjustment unit 11H detects whether the bus voltage (corresponding to the output voltage of the solar power generation device 30) is greater than or equal to a predetermined threshold value V thresh and increasing the charging current to the electric vehicle 20 when the bus voltage is not below a threshold V thresh When the charging current to the electric vehicle 20 is below the threshold value V, the charging current to the electric vehicle 20 is reduced, thereby adjusting the charging current to the electric vehicle 20. threshis set higher than the surplus power threshold for determining whether or not there is surplus power in the photovoltaic power generation device 30, and is set to about 54 V when the system power supply (rectifier 50 and commercial power supply 60) is 48 V DC.

[0037] The charging control unit 11G is a functional unit that performs control so that surplus power of the solar power generation device 30 is charged to the electric vehicle 20 by the charging current adjusted by the charging current adjustment unit 11H.

[0038] As shown in Fig. 9, the second embodiment differs from the first embodiment in that, when surplus power occurs in the solar power generation device 30 during operation in the discharge pattern operation mode (i.e., during the loop of steps S1 to S3 in Fig. 9) (YES in step S3), the process proceeds to step S5, and an operation mode decision process (Fig. 10) for charge pattern 2, which is different from charge pattern 1, is executed. The operation mode decision process for charge pattern 2, which relates to this difference, will be described below.

[0039] In step S5 (processing of FIG. 10), the operation mode determination unit 11D determines whether the SOC LIB It is determined whether the storage battery 40 is in a fully charged state based on whether the SOC of the electric vehicle 20 has reached 100% (or a predetermined value close to 100%) (step S51). EV It is determined whether the electric vehicle 20 is in a fully charged state depending on whether the charge reaches 100% (or a predetermined value close to 100%) (steps S52, S55).

[0040] Here, in the cases where (1) the storage battery 40 is not fully charged but the electric vehicle 20 is fully charged (NO in steps S51 and YES in S55), (2) the storage battery 40 is fully charged but the electric vehicle 20 is not fully charged (YES in steps S51 and NO in S52), and (3) both the storage battery 40 and the electric vehicle 20 are fully charged (YES in steps S51 and YES in S52), as in the first embodiment, operation modes 6, 5, and 7 are respectively determined (steps S56, S54, S53), and an operation is executed to supply power from the rectifier 50 or the solar power generation device 30 to the electric vehicle 20, the storage battery 40, and the communication load 70 based on the respective operation mode.

[0041] On the other hand, (4) if neither the storage battery 40 nor the electric vehicle 20 is in a fully charged state (NO in step S51 and NO in step S55), the charging current adjustment unit 11H detects whether the bus voltage V is equal to or lower than a predetermined threshold value V thresh Depending on the result of the determination as to whether the battery voltage Vcc has fallen below 10 V, the charge amount adjustment is performed as follows, in which the charge amount to the electric vehicle 20 is increased or decreased by a small amount.

[0042] Specifically, the charging current adjustment unit 11H detects whether the bus voltage V is greater than or equal to a threshold V thresh If it is not less than the charge amount I EV In this case, the charge amount I EV is set to a predetermined initial value I0 (for example, 1A) and the minute amount dl is set to, for example, 1A, the charging current adjustment unit 11H adjusts the charging amount I EV becomes (I0+dl) and is adjusted to 2A. If the situation remains the same, the charge amount I EV is further increased by a minute amount dl. In step S60, the operation mode is determined to be operation mode 4 (an operation mode in which power from the rectifier 50 or the solar power generation device 30 is supplied to the electric vehicle 20, the storage battery 40, and the communication load 70), and the charging control unit 11G executes an operation of supplying power from the rectifier 50 or the solar power generation device 30 to the electric vehicle 20, the storage battery 40, and the communication load 70 based on the operation mode.

[0043] Then, the bus voltage V exceeds the threshold V thresh When the charge amount I EV After confirming that the charge amount I EV In order to switch the adjustment from "increase" to "decrease," the sign of the minute amount dl is reversed (to minus) (step S59). Then, in step S60, the charge amount I EV By adding a negative small amount dl to the EV is reduced by the absolute value of a minute amount dl, the operation mode is set to operation mode 4, and the power from the rectifier 50 or the solar power generation device 30 is supplied to the electric vehicle 20, the storage battery 40, and the communication load 70 based on the operation mode. For example, EV When the bus voltage V is set to 3A, the threshold V thresh When it falls below the charge level I EV is reduced by 1A and adjusted to 2A.

[0044] In this way, in step S60, EV =I EV If the "+dl" process is executed after the NO determination in step S57, the charging amount I EV On the other hand, if the process is executed after the NO determination in step S58, the charging amount I EV This is a process to reduce the

[0045] In addition, the bus voltage V exceeds the threshold V thresh (YES in step S57), and the charge amount I EV If it is confirmed that the count has reached 0 (YES in step S58), then since there is no charging of the electric vehicle 20, the operation mode is determined to be operation mode 6 (an operation mode in which power from the rectifier 50 or the solar power generation device 30 is supplied to the storage battery 40 and the communication load 70) (step S61), and based on this operation mode, an operation is executed to supply power from the rectifier 50 or the solar power generation device 30 to the storage battery 40 and the communication load 70.

[0046] As in the second embodiment described above, when surplus power is generated in the solar power generation device 30 and neither the storage battery 40 nor the electric vehicle 20 is in a fully charged state, the bus voltage V, which is equal to the output voltage of the solar power generation device 30, is equal to the threshold voltage V thresh When the charge amount to the electric vehicle 20 is not below I EV When the bus voltage V exceeds the threshold V thresh When the current is below I EV By reducing the current, it becomes possible to charge the electric vehicle 20 with the maximum amount of charge without interfering with the charging of the storage battery 40, without causing the bus voltage to become unstable, and without purchasing extra commercial power. Note that it is assumed that the charging of the storage battery 40 is performed by the potential difference between the output voltage of the photovoltaic power generation device 30 and the storage battery 40, and therefore no charging circuit is required.

[0047] [About modified examples] In the DC power supply systems of the first and second embodiments described above, the communication load 70 in Fig. 1 is not limited to a communication device, and may be other devices that consume power. Also, in the DC power supply systems of the first and second embodiments, the control device 10 is configured to have an EV converter function, but the EV converter may be provided independently outside the control device 10. Also, the voltage sensor 13 is configured to be provided inside the control device 10, but it may be provided outside the control device 10.

[0048] The block diagrams used to explain the above embodiments show functional blocks. These functional blocks (components) are realized by any combination of at least one of hardware and software. The method of realizing each functional block is not particularly limited. That is, each functional block may be realized by using one device that is physically or logically combined, or may be realized by using two or more devices that are physically or logically separated and directly or indirectly connected (for example, by wire, wirelessly, etc.). The functional blocks may be realized by combining the one device or the multiple devices with software.

[0049] Functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs the function of transmission is called a transmitting unit or a transmitter. As described above, there is no particular limitation on the method of realization of each of these.

[0050] For example, the control unit in an embodiment of the present disclosure may function as a computer that performs the processing in this embodiment. Fig. 11 is a diagram showing an example of a hardware configuration of a control device 10 according to an embodiment of the present disclosure. The above-mentioned control device 10 may be physically configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, and the like.

[0051] In the following description, the term "apparatus" may be interpreted as a circuit, a device, a unit, etc. The hardware configuration of the control device 10 may be configured to include one or more of the devices shown in the drawings, or may be configured to exclude some of the devices.

[0052] Each function in the control device 10 is realized by loading a specific software (program) onto hardware such as a processor 1001 and a memory 1002, causing the processor 1001 to perform calculations, control communication by the communication device 1004, and control at least one of the reading and writing of data in the memory 1002 and the storage 1003.

[0053] The processor 1001 controls the entire computer by running, for example, an operating system. The processor 1001 may be configured with a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, and the like.

[0054] Furthermore, the processor 1001 reads out programs (program codes), software modules, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002, and executes various processes according to these. As the programs, those that cause a computer to execute at least a part of the operations described in the above-mentioned embodiments are used. Although the above-mentioned various processes have been described as being executed by one processor 1001, they may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The programs may be transmitted from a network via a telecommunications line.

[0055] The memory 1002 is a computer-readable recording medium, and may be configured by at least one of, for example, a Read Only Memory (ROM), an Erasable Programmable ROM (EPROM), an Electrically Erasable Programmable ROM (EEPROM), a Random Access Memory (RAM), etc. The memory 1002 may be called a register, a cache, a main memory (primary storage device), etc. The memory 1002 can store a program (program code), software modules, etc. that are executable to implement a wireless communication method according to an embodiment of the present disclosure.

[0056] Storage 1003 is a computer-readable recording medium, and may be composed of at least one of, for example, an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray (registered trademark) disk), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy (registered trademark) disk, a magnetic strip, and the like. Storage 1003 may be referred to as an auxiliary storage device. The above-mentioned storage medium may be, for example, a database, a server, or other suitable medium including at least one of memory 1002 and storage 1003.

[0057] The communication device 1004 is hardware (transmission / reception device) for performing communication between computers via at least one of a wired network and a wireless network, and is also called, for example, a network device, a network controller, a network card, or a communication module.

[0058] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that accepts input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that performs output to the outside. The input device 1005 and the output device 1006 may be integrated (e.g., a touch panel). Each device such as the processor 1001 and the memory 1002 is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0059] Each aspect / embodiment described in this disclosure may be used alone, in combination, or switched according to execution. In addition, notification of specific information (e.g., notification that "X is the case") is not limited to being done explicitly, but may be done implicitly (e.g., not notifying the specific information).

[0060] Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described in the present disclosure. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure.

[0061] The order of the steps, sequences, flow charts, etc. of each aspect / embodiment described in this disclosure may be changed unless inconsistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the particular order presented.

[0062] The input and output information may be stored in a specific location (e.g., memory) or may be managed using a management table. The input and output information may be overwritten, updated, or added to. The output information may be deleted. The input information may be transmitted to another device.

[0063] As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0064] When the terms "include," "including," and variations thereof are used in this disclosure, these terms are intended to be inclusive, similar to the term "comprising." Further, when used in this disclosure, the term "or" is not intended to be an exclusive or.

[0065] In this disclosure, where articles have been added due to translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0066] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different." [Explanation of symbols]

[0067] 1...DC power supply system, 10...control device, 11...control unit, 11A...timer unit, 11B...bus voltage monitoring unit, 11C...pattern determination unit, 11D...operation mode determination unit, 11E...battery status monitoring unit, 11F...EV status monitoring unit, 11G...charging control unit, 11H...charging current adjustment unit, 12...charging / discharging switching unit, 13...voltage sensor, 14...charging / discharging unit, 20...electric vehicle, 30...solar power generation device, 40...battery, 50...rectifier, 60...commercial power supply, 70...communication load (load), 1001...processor, 1002...memory, 1003...storage, 1004...communication device, 1005...input device, 1006...output device, 1007...bus.

Claims

1. Electric cars and A storage battery, A solar power generation device; A rectifier that converts AC current supplied from a commercial power source into DC current and supplies DC power to a load; A control device that performs control related to charging and discharging; Equipped with The control device includes: a pattern determination unit that determines a pattern related to charging and discharging from a charging pattern and a discharging pattern based on the presence or absence of surplus power in the solar power generation device and current time information; an operation mode determination unit that determines one operation mode in the pattern determined by the pattern determination unit based on a result of comparing a charge state indicator of the electric vehicle with a predetermined reference value and a result of comparing a charge state indicator of the storage battery with a predetermined reference value, and performs control related to charging and discharging based on the determined operation mode; Including, DC power system.

2. The pattern determination unit is determining that there is surplus power in the solar power generation device when an output voltage of the solar power generation device exceeds a predetermined surplus power threshold; 2. The DC power supply system according to claim 1.

3. The pattern determination unit is determining a pattern related to charging and discharging as the charging pattern when the current time is a daytime time during which power generation in the solar power generation device is expected and it is determined that there is surplus power in the solar power generation device, and when the current time is a nighttime time other than the daytime time; determining, when the current time is a daytime time during which power generation in the solar power generation device is expected and it is determined that there is no surplus power in the solar power generation device, that the pattern related to charging and discharging is the discharging pattern; 3. The DC power supply system according to claim 1 or 2.

4. The operation mode determination unit is When the determined pattern is a discharge pattern, determining one operation mode from a plurality of operation modes including an operation mode in which power from at least one of the electric vehicle and the storage battery and the solar power generation device is supplied to the load, and an operation mode in which power from the rectifier is supplied to the load; When the determined pattern is a charging pattern, one operation mode is determined from a plurality of operation modes including an operation mode in which the power from the rectifier or the solar power generation device is supplied to at least one of the electric vehicle and the storage battery and the load, and an operation mode in which the power is supplied only to the load; A DC power supply system according to any one of claims 1 to 3.

5. The operation mode determination unit determines an operation mode in the discharge pattern as follows: when the charge state index of the electric vehicle exceeds an alert value which is a threshold value for determining that a decrease in the charge state index of the electric vehicle should be alerted, the alert value being set higher than a predetermined lower limit value, determining an operation mode 1 in which power is supplied from the electric vehicle and the solar power generation device to the load; when the charge state index of the electric vehicle is equal to or less than the alert value and exceeds the lower limit value, determining an operation mode 2 in which power is supplied from the electric vehicle, the storage battery, and the solar power generation device to the load; when the charge state index of the electric vehicle is equal to or lower than the lower limit and the charge state index of the storage battery is higher than a predetermined lower limit of the charge state index of the storage battery, determining an operation mode 3 in which power from the storage battery and the solar power generation device is supplied to the load; determining an operation mode 0 in which power from the rectifier is supplied to the load when the charge state indicator of the storage battery is equal to or less than the storage battery lower limit; 5. The DC power supply system according to claim 4.

6. The operation mode determination unit determines an operation mode in the charging pattern. determining an operation mode 4 in which power from the rectifier or the solar power generation device is supplied to the electric vehicle, the storage battery, and the load when the charge state indicator of the storage battery does not indicate a full charge and when the charge state indicator of the electric vehicle does not indicate a full charge; determining an operation mode 5 in which power from the rectifier or the solar power generation device is supplied to the electric vehicle and the load when the charge state indicator of the storage battery indicates a full charge and the charge state indicator of the electric vehicle does not indicate a full charge; determining an operation mode 6 in which power from the rectifier or the photovoltaic power generation device is supplied to the storage battery and the load when the charge state indicator of the storage battery does not indicate a full charge and the charge state indicator of the electric vehicle indicates a full charge; When the charge state indicator of the storage battery indicates a full charge and the charge state indicator of the electric vehicle indicates a full charge, determining an operation mode 7 in which power from the rectifier or the solar power generation device is supplied to the load; 6. A DC power supply system according to claim 4 or 5.

7. The operation mode determination unit is a charging current adjustment unit that adjusts the charging current to the electric vehicle by increasing the charging current to the electric vehicle when the output voltage of the solar power generation device is not below a threshold voltage set higher than a predetermined surplus power threshold, and by reducing the charging current to the electric vehicle when the output voltage of the solar power generation device is below the threshold voltage, when the charging state index of the storage battery does not indicate full charge and the charging state index of the electric vehicle does not indicate full charge; a charging control unit that controls the charging current adjusted by the charging current adjustment unit so that surplus power from the solar power generation device is charged to the electric vehicle; Including, A DC power supply system according to any one of claims 1 to 6.

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