JP2016116428A - Autonomous operation system for distributed power source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an autonomous operation system for a distributed power supply system capable of preventing reduction of peak cut effects by controlling discharge power of a plurality of power storage facilities.SOLUTION: The autonomous operation system (autonomous operation system 100a) for a distributed power source which reduces power from a commercial system comprises: a plurality of power conversion parts (inverters 120a-1 to 120a-3) which compensate for power fluctuation at a power receiving point (power receiving point P1) of power from the commercial system while system-interlocking with the commercial system and using a storage battery; and a control part (control part 110a) by which, if the power at the power receiving point is equal to or higher than a preset target power value, the plurality of power conversion parts are controlled and power is discharged from the storage battery. The control part controls discharge power from each of the plurality of power conversion parts in accordance with SOC of the storage battery connected to the plurality of power conversion parts.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an autonomous operation system for a distributed power source (microgrid).

  As a social trend after full liberalization of power, distributed power sources (natural gas cogeneration and fuel cells) are likely to enter the building as energy supply facilities. The challenge is how to connect the new energy represented by these distributed power sources and solar power generation without placing a burden on the commercial grid (the power company's power grid). As a countermeasure, efforts to “microgrid”, which reduces the burden on the commercial system through load following operation of distributed power sources, are becoming active.

  In an energy supply system using a distributed power supply that incorporates the idea of microgrid (hereinafter simply referred to as “microgrid”), peak cut operation is normally performed in cooperation with the commercial grid, and the power supply of the commercial grid is cut off. It can be considered to be used as a power source for BCP (Business Continuity Plan). However, since natural energy power generation using natural energy such as solar and wind power fluctuates greatly due to changes in the weather and the environment, fluctuations are necessary for reliable peak cut operation during grid operation. Accordingly, it is necessary to control the output of the storage battery.

In order to operate a microgrid, a storage facility with sufficient capacity is indispensable. Since power storage equipment is high at present, it is assumed that a power storage equipment with sufficient capacity cannot be introduced and the microgrid cannot exhibit 100% of the function. For example, in a microgrid using a storage battery and solar power generation, when the power load is stabilized near the maximum demand, there is a concern that a sufficient peak cut effect cannot be expected due to insufficient capacity of the power storage facility.
For example, Patent Document 1 discloses an autonomous operation system of a distributed power source that performs peak cut operation with one storage battery.

JP 2013-247795 A

  However, in the autonomous operation system of the distributed power source described in Patent Document 1, since the peak cut operation is performed by one storage battery, a sufficient peak cut effect cannot be expected due to insufficient capacity of the power storage facility. Therefore, it is conceivable to use a plurality of power storage facilities in order to prevent a shortage of the capacity of the power storage facility. However, in this method, when the SOC (State of Charge, state of charge) of the plurality of power storage facilities differs, the peak cut effect is reduced. May occur.

  The present invention has been made in view of the above points, and a main object of the present invention is to provide an autonomous operation system for a distributed power supply system that can control the discharge power of a plurality of power storage facilities to prevent a reduction in peak cut effect. It is to provide.

In order to solve the above problem, an autonomous operation system of a distributed power source of the present invention is an autonomous operation system of a distributed power source that reduces power from a commercial system, and is interconnected with the commercial system, Compensating for power fluctuations at a power receiving point of power from the commercial system using a storage battery, and when the power at the power receiving point is equal to or higher than a preset target power value, the plurality of power conversions A control unit that controls the unit to discharge power from the storage battery, and the control unit discharges power of each of the plurality of power conversion units according to the SOC of the storage battery connected to the plurality of power conversion units. It is characterized by controlling.
With this configuration, in the autonomous operation system of the distributed power source according to the present invention, the control unit controls the discharge power of each of the plurality of power conversion units according to the SOC of the storage battery connected to the plurality of power conversion units. Therefore, it is possible to prevent the peak cut effect from decreasing.

In the autonomous operation system for distributed power sources according to the present invention, the control unit controls the discharge power of each of the plurality of power conversion units in proportion to the SOC of a storage battery connected to each of the plurality of power conversion units. It is characterized by that.
With this configuration, the time until the SOC of the storage battery in each power conversion unit becomes 0% can be made the same, so the power of the storage battery can be used for peak cut operation without waste.

Further, in the autonomous operation system of the distributed power source according to the present invention, the control unit sets a higher discharge power for a storage battery having a higher SOC so that the SOC of the storage battery connected to each of the plurality of power conversion units is equal, It is characterized by discharging from each of a plurality of power conversion parts.
With this configuration, the time until the SOC of the storage battery in each power conversion unit becomes 0% can be made the same, so the power of the storage battery can be used for peak cut operation without waste.

  ADVANTAGE OF THE INVENTION According to this invention, the autonomous operation system of the distributed power supply system which can control the discharge electric power of several electrical storage equipment and can prevent the reduction | decrease in a peak cut effect can be provided.

It is a schematic block diagram which shows the structural example of the autonomous operation system 100 of a general distributed type power supply. It is a figure for demonstrating the effect of the peak cut driving | operation in the autonomous driving system 100 shown in FIG. It is a schematic block diagram which shows the structural example of the autonomous operation system 100a of the distributed power supply of 1st Embodiment. It is a figure for demonstrating the effect of the peak cut driving | operation in the autonomous driving system 100a shown in FIG. It is a schematic block diagram which shows the structural example of the autonomous operation system 100b of the distributed power supply of 2nd Embodiment. It is a flowchart which shows the control processing in the peak cut driving | operation in the autonomous driving system 100b shown in FIG. It is a figure for demonstrating the effect of the peak cut driving | operation in the autonomous driving system 100b shown in FIG.

An autonomous operation system of a distributed power source according to the present invention is an autonomous operation system of a distributed power source that reduces power from a commercial system, and is connected to the commercial system to receive power at a power receiving point of power from the commercial system. A plurality of power conversion units that perform compensation of fluctuation using a storage battery, and a control unit that controls the plurality of power conversion units and discharges power from the storage battery when the power at the power receiving point is equal to or higher than a preset target power value The control unit controls the discharge power of each of the plurality of power conversion units according to the SOC of the storage battery connected to the plurality of power conversion units.
Hereinafter, the first embodiment and the second embodiment will be described with respect to the point of controlling the discharge power of each of the plurality of power conversion units according to the SOC of the storage battery connected to the plurality of power conversion units, which is a feature of the present application. Before describing, an example of controlling a power conversion unit connected to storage batteries having different values of SOC will be described.
FIG. 1 is a schematic block diagram illustrating a configuration example of a general distributed power supply autonomous operation system (hereinafter, referred to as an autonomous operation system 100).
The autonomous driving system 100 includes a control unit 110, an inverter 120-1, an inverter 120-2, an inverter 120-3, a storage battery 130-1, a storage battery 130-2, a storage battery 130-3, a solar power generation device 150, and a building load 160. Prepare.

The control unit 110 transmits a charge / discharge command value to each of the inverter 120-1, the inverter 120-2, and the inverter 120-3 (a plurality of power conversion units, hereinafter may be referred to as the inverter 120), to each inverter. It controls charging to the connected storage battery and discharging from the storage battery connected to each inverter. Note that the number of inverters 120 is not limited to three but may be two or more.
Here, the storage battery connected to inverter 120-1 is storage battery 140-1 provided in storage battery 130-1 and EV (Electric Vehicle) 1. In addition, the storage battery connected to the inverter 120-2 is the storage battery 140-2 included in the storage battery 130-2 and EV2. The storage battery connected to the inverter 120-3 is the storage battery 140-3 provided in the storage battery 130-3 and EV3. Hereinafter, storage battery 130-1 to storage battery 130-3 may be referred to as storage battery 130, and storage battery 140-1 to storage battery 140-3 may be referred to as EV storage battery 140.
The EV storage battery 140 is connected to the inverter 120 because the SOC varies depending on the EV travel distance, the charging time, and the like. Of course, not only the EV storage battery 140 but also the storage battery 130 connected to the inverter 120, the SOC may be different in each inverter 120. Further, here, the storage battery 130 and the EV storage battery 140 are connected one by one in each inverter 120, but either one of them may be connected. Moreover, although the storage battery demonstrated the storage battery 130 and the EV storage battery 140 as an example, a storage battery is not restricted to these. That is, for example, a device other than EV can be used as long as it is a device equipped with a storage battery.

  The control unit 110 detects the power at the power receiving point 210 of the power line 200, and when the detected power is equal to or higher than a preset target power value (power purchase target power value), transmits a discharge command value to each inverter. Each inverter performs control to discharge the electric power of the storage battery with electric power equal to or lower than the rated electric power. This is called peak cut operation. The condition for executing the peak cut operation may be a case where the load power of the building load 160 is equal to or higher than the target power value. In addition, the control unit 110 detects the power at the power receiving point 210 of the power line 200, and when the detected power is equal to or less than a preset target power value, transmits a charge command value to each inverter, and each inverter Control is performed to charge the storage battery with the power discharged from the storage battery in the peak cut operation using the power from 400.

  The inverter 120 is a bidirectional power conversion device that performs bidirectional power conversion between alternating current and direct current. Inverter 120 converts alternating current into direct current in the charging operation when charging the storage battery from commercial system 400 and solar power generation device 150, and converts direct current into alternating current in the operation mode when discharging from storage battery to building load 160. Moreover, the inverter 120 can selectively perform charging / discharging with respect to the storage battery 140 mounted in the storage battery 130 and EV.

  The solar power generation device 150 includes a solar cell 151 and a power conditioner (PCS) 152, and is a device that performs solar power generation. The solar power generation device 150 can supply the generated power to the building load 160 through the power line 200. Moreover, the solar power generation device 150 can supply charging power to the storage battery connected to the inverter 120 via the inverter 120 from the power line 200.

  The building load 160 is a load to which power from the commercial system 400, the solar power generation device 150, and the inverter 120 is supplied. Specifically, the building load 160 is used for power of various electronic devices and lighting provided in the autonomous driving system 100. It becomes a device or appliance to consume.

The peak cut operation of the autonomous driving system 100 having the above configuration will be described.
The controller 110 monitors the power value of the power receiving point 210 and determines the discharge power (total) Pd [kW] of the inverters 120-1 to 120-3 necessary for the peak cut operation. In the general autonomous driving system 100, when there are three inverters 120, the control unit 110 transmits a discharge command value of Pd ÷ 3 [kW] to each of the inverters 120-1 to 120-3. Thereby, the inverter 120 performs the peak cut operation by the discharge power (total) Pd [kW]. However, for example, when the SOCs of the storage battery 130-1 and the storage battery 140-1 connected to the inverter 120-1 are low, if the discharge is continued as it is, the storage battery 130-1 and the storage battery 140-1 connected to the inverter 120-1 The SOC becomes 0% faster than other inverters, and the discharge from the inverter 120-1 stops. After that, the discharge from the two inverters 120-2 and 120-3 results in a reduction in the peak cut effect. The peak cut effect means that discharge can be performed by the discharge power (total) Pd, and the reduction of the peak cut effect means that the discharge power (total) is reduced from the discharge power (total) Pd.

The reduction of the peak cut effect will be described with reference to FIG. FIG. 2 is a diagram for explaining the effect of the peak cut operation in the autonomous driving system 100 shown in FIG. FIG. 2 shows the time transition of the SOC of each of the inverters 120, the discharge power (total) of the inverters 120 [kW], and the total SOC of the storage batteries connected to each of the inverters 120.
For simplicity of explanation, it is assumed that the storage battery 130 is not connected to the inverter 120 and the EV storage battery 140 is connected. Here, it is assumed that the storage capacity of the EV storage battery 140 is 100 kWh, the storage battery 140-1 is discharged from a state where the SOC is 50%, and the storage battery 140-2 and the storage battery 140-3 are discharged from the state where the SOC is 100%. . Further, it is assumed that the command of the discharge power value (total) Pd [kW] from the control unit 110 is 25 kW, and the rated output of each inverter 120 is 10 kW.
The amount of stored power of storage battery 140-1 connected to inverter 120-1 is 50 kWh at the start of discharge, and the discharge power of inverter 120-1 is 25/3 kW, so 50 [kWh] ÷ 25/3 [kW] ] After 6 [h], it becomes 0 kWh. As shown in FIG. 2, after 360 minutes (6 hours) from the start of discharge, the SOC of the storage battery 140-1 connected to the inverter 120-1 becomes 0%, and the discharge is stopped. Thereafter, the discharge power (total) decreases from 25 kW to 25 [kW] × (2/3) = 16.7 [kW], and the peak cut effect decreases.

  The reason why the peak cut effect is lowered is that the discharge power is set to the same value between the inverter having a small SOC of the connected storage battery and the inverter having a large SOC of the connected storage battery. Therefore, in the embodiment described below, the discharge power of each of the inverters 120 is set to a value corresponding to the SOC of each of the storage batteries connected to each of the inverters 120, so that Is not 0 kW first, but 0 kW at the same time. Further, the discharge power of each of the storage batteries of the inverter 120 is controlled by discharging from each so that the discharge power (total) of the inverter 120 becomes the discharge power (total) Pd. This prevents a decrease in peak cut effect.

(First embodiment)
FIG. 3 is a schematic block diagram illustrating a configuration example of the autonomous operation system 100a of the distributed power source according to the first embodiment. 3, the same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.
In FIG. 3, the control unit 110 shown in FIG. 1 is the control unit 110a, the inverter 120-1 is the inverter 120a-1, the inverter 120-2 is the inverter 120a-2, and the inverter 120-3 is the inverter 120a-3. .

  Inverter 120a-1 shown in FIG. 3 transmits SOC1, which is the total SOC of connected storage battery 130-1 and storage battery 140-1, to control unit 110a. Inverter 120a-2 transmits SOC2 that is the total SOC of connected storage battery 130-2 and storage battery 140-2 to control unit 110a. Inverter 120a-3 transmits SOC3, which is the total SOC of connected storage battery 130-3 and storage battery 140-3, to control unit 110a. This is because control unit 110a determines discharge power P1 of inverter 120a-1, discharge power P2 of inverter 120a-2, and discharge power P3 of inverter 120a-3 based on SOC1 to SOC3. The controller 110a determines the discharge power Pn of the nth inverter 120a-n by the following equation (1). In the following formula, N is the total number of inverters 120a (N = 3 in this embodiment). The SOCn is the total SOC of the storage battery 130-n and storage battery 140-n connected to the nth 120a-n. Pd is the discharge power value (total value) of the inverters 120a-1 to 120a-N.

The peak cut operation of the autonomous driving system 100a having the above configuration will be described with reference to FIG. FIG. 4 is a diagram for explaining the effect of the peak cut operation in the autonomous driving system 100a shown in FIG. FIG. 4 shows the time transition of the SOC of each of the inverters 120a, the discharge power (total) of the inverters 120a (kW), and the total SOC of the storage batteries connected to each of the inverters 120a.
For simplicity of explanation, it is assumed that the storage battery 130 is not connected to the inverter 120a and the EV storage battery 140 is connected. Here, it is assumed that the storage capacity of the EV storage battery 140 is 100 kWh, the storage battery 140-1 is discharged from a state where the SOC is 50%, and the storage battery 140-2 and the storage battery 140-3 are discharged from the state where the SOC is 100%. . That is, at the start of the peak cut operation, the stored power amount of the storage battery 140-1 is 50 kWh, the stored power amount of the storage battery 140-2 is 100 kWh, and the stored power amount of the storage battery 140-3 is 100 kWh. Further, it is assumed that the command of the discharge power (total) Pd from the control unit 110a is 25 kW, and the rated output of each inverter 120 is 10 kW.
In the peak cut operation, EV1 to EV3 do not leave the autonomous driving system 100a, and the inverter 120a can discharge from the storage batteries 140-1 to 140-3.

  Since the SOC1 is 50% and the total value of SOC1 to SOC3 is 250% at the start of discharge, the controller 110a has a discharge power P1 of 25 [kW] × 50 [%] / 250 [%] = 5 [kW]. Is transmitted to the inverter 120a-1. Moreover, since the SOC2 is 100% and the total value of SOC1 to SOC3 is 250% at the start of discharge, the controller 110a discharges 25 [kW] × 100 [%] / 250 [%] = 10 [kW]. A discharge command value indicating power P2 is transmitted to inverter 120a-2. In addition, since the SOC3 is 100% and the total value of SOC1 to SOC3 is 250% at the start of discharge, the controller 110a discharges 25 [kW] × 100 [%] / 250 [%] = 10 [kW]. A discharge command value indicating electric power P3 is transmitted to inverter 120a-3.

The control unit 110a periodically reviews the discharge power P1 to P3 of the inverters 120a-1 to 120a-3 by the above formula (1) (for example, every minute).
For example, SOC1 to SOC3 after 120 minutes (2h) are as follows. Since the storage power amount 50 kWh at the start of discharging of the storage battery 140-1 connected to the inverter 120a-1 is 50 [kWh] -5 [kW] × 2 [h] = 40 [kWh], SOC1 is 40%. become. Since the storage power amount 100 kWh at the start of discharging of the storage battery 140-2 connected to the inverter 120a-2 is 100 [kWh] -10 [kW] × 2 [h] = 80 [kWh], SOC2 is 80%. become. Since the storage power amount 100 kWh at the start of discharging of the storage battery 140-3 connected to the inverter 120a-3 is 100 [kWh] -10 [kW] × 2 [h] = 80 [kWh], SOC3 is 80%. become.

  Since the SOC1 is 40% and the total value of SOC1 to SOC3 is 200% after 120 minutes, the control unit 110a has a discharge power P1 of 25 [kW] × 40 [%] / 200 [%] = 5 [kW]. Is transmitted to the inverter 120a-1. Further, after 120 minutes, since the SOC2 is 80% and the total value of SOC1 to SOC3 is 200%, the control unit 110a discharges 25 [kW] × 80 [%] / 200 [%] = 10 [kW]. A discharge command value indicating power P2 is transmitted to inverter 120a-2. Further, after 120 minutes, since the SOC3 is 80% and the total value of SOC1 to SOC3 is 200%, the controller 110a discharges 25 [kW] × 80 [%] / 200 [%] = 10 [kW]. A discharge command value indicating electric power P3 is transmitted to inverter 120a-3. Thereby, the discharge power (total) Pd from the inverters 120a-1 to 120a-3 is maintained at 25 kW.

  The controller 110a reviews the discharge powers P1 to P3 of the inverters 120a-1 to 120a-3 by the above equation (1) even after 120 minutes. Since 5 kW of the discharge power P1 transmitted to the inverter 120a-1 is maintained, the stored power amount 40 kWh after 120 minutes from the start of discharge of the 140-1 connected to the inverter 120a-1 is 40 [kWh] ÷ 5. After [kW] = 8 [h], it becomes 0 kWh. Since 10 kW of the discharge power P2 transmitted to the inverter 120a-2 is maintained, the stored power amount 80 kWh after 120 minutes from the start of discharge of the 140-2 connected to the inverter 120a-2 is 80 [kWh] ÷ 10. After [kW] = 8 [h], it becomes 0 kWh. Since 10 kW of the discharge power P3 transmitted to the inverter 120a-3 is maintained, the stored power amount 80 kWh after 120 minutes from the start of discharge of the 140-3 connected to the inverter 120a-3 is 80 [kWh] ÷ 10. After [kW] = 8 [h], it becomes 0 kWh.

  In this way, the amount of power stored in storage battery 140-1 to storage battery 140-3 of inverter 120a simultaneously becomes 0 kWh after 10 hours (600 minutes) have elapsed since the start of peak cut operation. That is, in the autonomous driving system 100 described above, the discharge power (total) Pd from the inverter 120 can be maintained only for 6 hours. On the other hand, in the autonomous driving system 100a, the time for maintaining the discharge power (total) Pd from the inverter 120a can be extended to 8 hours. Moreover, the control part 110a maintains discharge electric power (total) Pd at 25 kW until it stops discharge by reexamining discharge electric power P1-P3 of inverter 120a-1-inverter 120a-3 by said Formula (1). Therefore, it is possible to use the power (storage power amount) of the storage battery for peak cut without waste.

  As described above, the control unit 110a includes the storage batteries (storage battery 130-1 to storage battery 130-3, storage battery 140-1 to storage battery 140-) connected to each of the plurality of power conversion units (inverters 120a-1 to 120a-3). The discharge power of each of the plurality of power conversion units is controlled in proportion to the SOC of 3). With this configuration, the time until the SOC of the storage battery in each power conversion unit becomes 0% can be made the same, so the power of the storage battery can be used for peak cut operation without waste.

(Second Embodiment)
FIG. 5 is a schematic block diagram illustrating a configuration example of the autonomous operation system 100b of the distributed power source according to the second embodiment. In FIG. 5, the same portions as those in FIG. 3 are denoted by the same reference numerals, and the description thereof is omitted.
In FIG. 5, the control unit 110a shown in FIG. 3 is a control unit 110b. According to the following procedure, the discharge powers P1 to PN of the N inverters 120a-1 to 120a-N are determined according to the flowchart shown in FIG. FIG. 6 is a flowchart showing a control process in the peak cut operation in the autonomous driving system 100b shown in FIG.
Below, the peak cut operation | movement of the autonomous driving system 100b is demonstrated with reference to FIG.6 and FIG.7. FIG. 7 is a diagram for explaining the effect of the peak cut operation in the autonomous driving system 100b shown in FIG. FIG. 7 shows the time transition of the SOC of each of the inverters 120a, the discharge power (total) of the inverters 120a [kW], and the total SOC of the storage batteries connected to each of the inverters 120a.
In order to simplify the description, the following description will be made assuming that N = 3. In addition, it is assumed that the storage battery 130 is not connected to the inverter 120a and the EV storage battery 140 is connected. Here, the storage capacity of the EV storage battery 140 is 100 kWh, the storage battery 140-1 discharges from an SOC of 80%, the storage battery 140-2 discharges from an SOC of 90%, and the storage battery 140-3 discharges from an SOC of 100%. Assuming that That is, at the start of the peak cut operation, the stored power amount of the storage battery 140-1 is 80 kWh, the stored power amount of the storage battery 140-2 is 90 kWh, and the stored power amount of the storage battery 140-3 is 100 kWh. Further, it is assumed that the command of the discharge power (total) Pd from the control unit 110b is 25 kW, and the rated output of each inverter 120 is 10 kW.
In the peak cut operation, EV1 to EV3 do not leave the autonomous driving system 100b, and the inverter 120a can discharge from the storage battery 140-1 to storage battery 140-3.

Control unit 110b substitutes discharge power (total value) Pd for Pdtmp (step ST1). For example, the control unit 110b stores the discharge power (total value) Pd in Pdtmp of the RAM included in the control unit 110b.
Control unit 110b assigns {inverter 120a-n, n = N} to set {A} (step ST2). {Inverter 120a-n, n = N} is a total of N inverters of inverter 120a-1 to inverter 120a-N. For example, the control unit 110b stores {inverters 120a-n, n = N} in a set of RAMs {A} included in the control unit 110b.
At the start of discharge, control unit 110b substitutes discharge power (total value) Pd = 25 [kW] for Pdtmp (step ST1). At the start of discharge, control unit 110b substitutes {inverter 120a-1, inverter 120a-2, inverter 120a-3} into set {A} (step ST2).

Control unit 110b extracts i-th inverter 120a-i having the maximum SOC from set {A} (step ST3). When there are a plurality of inverters having the maximum SOC, a plurality of inverters are selected.
At the start of discharge, control unit 110b extracts inverter 120a-3 because SOC3 is 100%, SOC2 is 90%, and SOC1 is 80% (step ST3).

Control unit 110b determines discharge power Pi of inverter 120a-i (step ST4). As a condition for determining the discharge power of the inverter 120a-i, the discharge power Pi that is the maximum among the conditions of Pdtmp or less and the rated output of the inverter 120a-i or less is set as the discharge power Pi. In addition, when there are a plurality of inverters 120a-i, the discharge power obtained by evenly distributing the total discharge power is discharged while the total discharge power satisfies the condition of Pdtmp or less and the rated output of the inverter 120a-i or less. The power Pi is set.
The controller 110b determines the discharge power P3 of the inverter 120a-3 as the discharge power P3 of the inverter 120a-3, at the start of discharge, Pdtmp = 25 [kW] or less and the maximum discharge power 10 kW satisfying the condition of the rated output 10kW or less of the inverter 120a-3 (Step ST4).

Control unit 110b subtracts discharge power Pi from Pdtmp (step ST5).
Control unit 110b removes inverter 120a-i from set {A} at the start of discharge (step ST6).
At the start of discharge, control unit 110b subtracts discharge power P3 = 10 [kW] from Pdtmp = 25 [kW] to set Pdtmp = 15 [kW] (step ST5). Control unit 110b removes inverter 120a-3 from set {A} at the start of discharge (step ST6).

  The control unit 110b determines whether or not Pdtmp = 0 [kW] (step ST7). When Pdtmp is not 0 kW (step ST7—No), the control unit 110b returns to step ST3. On the other hand, when Pdtmp = 0 [kW] (step ST7—Yes), the control unit 110b proceeds to step ST8. Control unit 110b determines whether set {A} is an empty set (step ST8). When the set {A} is an empty set (step ST8—Yes), the control unit 110b ends the process according to this flow. On the other hand, when the set {A} is not an empty set (step ST8-No), the control unit 110b proceeds to step ST9. The control unit 110b sets the discharge power of the inverters 120a-i in the set {A} to Pi = 0 [kW], and ends the process according to this flow (step ST9).

At the start of discharge, control unit 110b determines that Pdtmp is 15 kW and is not 0 (step ST7). Since Pdtmp is not 0 kW (No in Step ST7), the control unit 110b returns to Step ST3 and next selects the inverter 120a-i having the maximum SOC.
Control unit 110b extracts inverter 120a-2 because SOC2 is 90% and SOC1 is 80% at the start of discharge (step ST3). The controller 110b sets the discharge power P2 of the inverter 120a-2 to the maximum discharge power 10kW while satisfying the conditions of Pdtmp = 15 [kW] or less and the rated output 10kW or less of the inverter 120a-2 at the start of discharge. (Step ST4). At the start of discharge, control unit 110b subtracts discharge power P2 = 10 [kW] from Pdtmp = 15 [kW] to set Pdtmp = 5 [kW] (step ST5). Control unit 110b removes inverter 120a-2 from set {A} at the start of discharge (step ST6).
At the start of discharge, control unit 110b determines that Pdtmp is 5 kW and not 0 kW (step ST7). Since Pdtmp is not 0 kW (No in Step ST7), the control unit 110b returns to Step ST3 and next selects the inverter 120a-i having the maximum SOC.

  Control unit 110b extracts inverter 120a-1 because SOC1 is 80% at the start of discharge (step ST3). The control unit 110b sets the discharge power P1 of the inverter 120a-1 to a maximum discharge power of 5 kW while satisfying the conditions of Pdtmp = 5 [kW] or less and the rated output of the inverter 120a-2 of 10 kW or less. (Step ST4). At the start of discharge, control unit 110b subtracts discharge power P2 = 5 [kW] from Pdtmp = 5 [kW] to set Pdtmp = 0 [kW] (step ST5). Control unit 110b removes inverter 120a-1 from set {A} at the start of discharge (step ST6).

  The controller 110b determines that Pdtmp is 0 kW and 0 kW at the start of discharge (step ST7). Since the control unit 110b is in the case of Pdtmp = 0 [kW] (step ST7-Yes), the control unit 110b proceeds to step ST8. The control unit 110b determines whether or not the set {A} is an empty set (step ST8). Since the set {A} is an empty set (step ST8—Yes), the process according to this flow is terminated.

  As a result, the discharge power P3 of the inverter 120a-3 = 10 [kW], the discharge power P2 of the inverter 120a-2 = 10 [kW], and the discharge power P1 of the inverter 120a-1 = 5 [kW]. At the start of discharge, the controller 110b causes the inverter 120a to execute a peak cut operation with discharge power (total) Pd = 25 [kW].

Control unit 110b is connected to SOC1 of storage battery 140a-1 periodically connected to inverter 120a-1, SOC2 of storage battery 140a-2 connected to inverter 120a-2, and inverter 120a-3 even after the start of discharging. The SOC 3 of the storage battery 140a-3 is received and the above determination is made. Since the SOC2 of the storage battery 140a-2 connected to the inverter 120a-2 is 90% at the start of discharging, the stored power amount of the storage battery 140-2 is 90 kWh. Moreover, since SOC1 of the storage battery 140a-1 connected to the inverter 120a-1 is 80%, the stored electric energy of the storage battery 140-1 is 80 kWh.
Since the discharge power P2 of the inverter 120a-2 is 10 [kW] and the discharge power P1 of the inverter 120a-1 is 5 [kW], from the start of the discharge, (the stored power amount 90 [kWh] of the storage battery 140-2-storage battery 140-1 stored power amount 80 [kWh]) / (10 [kW] -5 [kW]) = 2 [h] (120 minutes), the SOC2 of the storage battery 140a-2 connected to the inverter 120a-2 And SOC1 of the storage battery 140a-1 connected to the inverter 120a-1.

After 120 minutes from the start of discharge, the SOC1 of the inverter 120a-1, the SOC2 of the inverter 120a-2, and the SOC3 of the inverter 120a-3 are as follows.
The storage power amount 100 kWh at the start of discharging of the storage battery 140-3 was discharged for 2 hours at the discharge power P1 = 10 [kW], so that 100 [kWh] −10 [kW] × 2 [h] = 80 [kWh] Therefore, SOC3 = 80 [%]. The storage power amount 90 kWh at the start of discharge of the storage battery 140-2 was discharged for 2 hours at the discharge power P2 = 10 [kW], so that 90 [kWh] −10 [kW] × 2 [h] = 70 [kWh] Therefore, SOC2 = 70 [%]. The stored power amount 80 kWh at the start of the discharge of the storage battery 140-1 was discharged for 2 hours at the discharge power P1 = 5 [kW], so that 80 [kWh] -5 [kW] × 2 [h] = 70 [kWh] Therefore, SOC1 = 70 [%].

The controller 110b determines the discharge powers P1 to P3 of the three inverters 120a-1 to 120a-3 according to the following procedure after 120 minutes from the start of discharge.
Control unit 110b substitutes discharge power (total value) Pd = 25 kW for Pdtmp after 120 minutes from the start of discharge (step ST1).
Control unit 110b substitutes {inverter 120a-1, inverter 120a-2, inverter 120a-3} into set {A} after 120 minutes from the start of discharge (step ST2).
Control unit 110b extracts inverter 120a-3 because SOC3 is 80%, SOC2 is 70%, and SOC1 is 70% after 120 minutes from the start of discharge (step ST3).
The controller 110b, after 120 minutes from the start of discharge, discharges 10kW, which is the maximum while satisfying the conditions of Pdtmp = 25 [kW] or less and the rated output of the inverter 120a-3 of 10kW or less. Electric power P3 is determined (step ST4).

After 120 minutes have elapsed from the start of discharge, control unit 110b subtracts discharge power P3 = 10 [kW] from Pdtmp = 25 [kW] to set Pdtmp = 15 [kW] (step ST5). Control unit 110b removes inverter 120a-3 from set {A} at the start of discharge (step ST6).
The controller 110b determines that Pdtmp is 15 kW and not 0 kW after 120 minutes from the start of discharge (step ST7). Since Pdtmp is not 0 kW (No in Step ST7), the control unit 110b returns to Step ST3 and next selects the inverter 120a-i having the maximum SOC.

The controller 110b extracts two inverters 120a-2 and 120a-2 because there are a plurality of inverters that have SOC2 of 70%, SOC1 of 70%, and the maximum SOC after 120 minutes from the start of discharge. (Step ST3).
After 120 minutes have elapsed from the start of discharge, the control unit 110b has a total discharge power of the inverter 120a-2 and the inverter 120a-2 of Pdtmp = 15 [kW] or less, and the rated output of the inverter 120a-2 and the inverter 120a-2. While satisfying the condition of 10 kW or less, the discharge power 7.5 kW obtained by uniformly distributing the total discharge power Pdtmp = 15 [kW] is set as the discharge power P2 and the discharge power P1 (step ST4).

The controller 110b subtracts the discharge power P2 = 7.5 [kW] and the discharge power P1 = 7.5 [kW] from Pdtmp = 15 [kW] after 120 minutes from the start of discharge, and Pdtmp = 0 [kW] ] (Step ST5).
Control unit 110b removes inverter 120a-2 and inverter 120a-1 from set {A} after 120 minutes from the start of discharge (step ST6).
The controller 110b determines that Pdtmp is 0 kW and 0 kW after 120 minutes from the start of discharge (step ST7). Since the control unit 110b is in the case of Pdtmp = 0 [kW] (step ST7-Yes), the control unit 110b proceeds to step ST8. The control unit 110b determines whether or not the set {A} is an empty set (step ST8). Since the set {A} is an empty set (step ST8—Yes), the process according to this flow is terminated.

  From the above, the discharge power P3 of the inverter 120a-3 = 10 [kW], the discharge power P2 of the inverter 120a-2 = 7.5 [kW], and the discharge power P1 of the inverter 120a-1 = 7.5 [kW]. It was. The controller 110b causes the inverter 120a to execute a peak cut operation with discharge power (total) Pd = 25 [kW] after 120 minutes have elapsed from the start of discharge.

Control unit 110b periodically includes SOC1 of storage battery 140a-1 connected to inverter 120a-1, SOC2 of storage battery 140a-2 connected to inverter 120a-2, and storage battery 140a-3 connected to inverter 120a-3. SOC3 is received and the above determination is made.
After 120 minutes from the start of discharge, the SOC2 of the storage battery 140a-3 connected to the inverter 120a-3 is 80%, and therefore the amount of stored power of the storage battery 140-2 is 80 kWh. Since the SOC2 of the storage battery 140a-2 connected to the inverter 120a-2 is 70%, the stored power amount of the storage battery 140-2 is 70 kWh. Moreover, since SOC1 of the storage battery 140a-1 connected to the inverter 120a-1 is 70%, the stored power amount of the storage battery 140-1 is 70 kWh.
The discharge power P3 of the inverter 120a-3 is 10 [kW], the discharge power P2 of the inverter 120a-2 is 7.5 [kW], and the discharge power P1 of the inverter 120a-1 is 7.5 [kW]. Therefore, after 120 minutes from the start of discharge, (storage battery 140-3 stored power amount 80 [kWh] −storage battery 140-2 or storage battery 140-1 stored power amount 70 [kWh]) ÷ (10 [kW] − 7.5 [kW]) = 4 [h] (240 minutes), after passing, SOC3 of the storage battery 140a-3 connected to the inverter 120a-3, SOC2 of the storage battery 140a-2 connected to the inverter 120a-2, SOC1 of storage battery 140a-1 connected to inverter 120a-1 becomes equal.

After 360 minutes from the start of discharge, SOC1 of inverter 120a-1, SOC2 of inverter 120a-2, and SOC3 of inverter 120a-3 are as follows.
Since the stored power amount 80 kWh after 120 minutes from the start of discharging of the storage battery 140-3 was discharged for 4 hours at the discharge power P1 = 10 [kW], 80 [kWh] -10 [kW] × 4 [h] = 40 Since it is [kWh], SOC3 = 40 [%]. The stored power amount 70 kWh after 120 minutes from the start of discharge of the storage battery 140-2 was discharged for 4 hours at the discharge power P2 = 7.5 [kW], so 70 [kWh] −7.5 [kW] × 4 [ Since h] = 40 [kWh], SOC2 = 40 [%]. The storage power amount 70 kWh after 120 minutes from the start of discharge of the storage battery 140-1 was discharged for 4 hours at the discharge power P1 = 7.5 [kW], so 70 [kWh] −7.5 [kW] × 4 [ Since h] = 40 [kWh], SOC1 = 40 [%].

The controller 110b determines the discharge powers P1 to P3 of the three inverters 120a-1 to 120a-3 by the following procedure after 360 minutes have elapsed from the start of discharge.
Control unit 110b substitutes discharge power (total value) Pd = 25 [kW] for Pdtmp after 360 minutes have elapsed from the start of discharge (step ST1).
Control unit 110b substitutes {inverter 120a-1, inverter 120a-2, inverter 120a-3} into set {A} after 360 minutes from the start of discharge (step ST2).

Since there are a plurality of inverters in which SOC3 is 40%, SOC2 is 40%, SOC1 is 40% and SOC is the maximum after 360 minutes from the start of discharge, the control unit 110b includes inverters 120a-3 and 120a-2. And three inverters 120a-2 are extracted (step ST3).
After 360 minutes have elapsed from the start of discharge, the controller 110b determines that the total discharge power of the inverter 120a-3, the inverter 120a-2, and the inverter 120a-2 is equal to or less than Pdtmp = 25 [kW], and the inverter 120a-2 and the inverter 120a. -2 with a rated output of 10 kW or less, the discharge power 25/3 kW obtained by uniformly distributing the total discharge power Pdtmp = 25 [kW] is set to the discharge power P3, the discharge power P2, and the discharge power P1 (step) ST4).

After 360 minutes have elapsed from the start of discharge, the control unit 110b starts from Pdtmp = 25 [kW] to discharge power P3 = 25/3 [kW], discharge power P2 = 25/3 [kW], and discharge power P1 = 25/3 [ kW] is subtracted to set Pdtmp = 0 [kW] (step ST5).
Control unit 110b removes inverter 120a-3, inverter 120a-2, and inverter 120a-1 from set {A} after the elapse of 360 minutes from the start of discharge (step ST6).
Control unit 110b determines that Pdtmp is 0 kW and 0 kW after 360 minutes have elapsed from the start of discharge (step ST7). Since the control unit 110b is in the case of Pdtmp = 0 [kW] (step ST7-Yes), the control unit 110b proceeds to step ST8. The control unit 110b determines whether or not the set {A} is an empty set (step ST8). Since the set {A} is an empty set (step ST8—Yes), the process according to this flow is terminated.

  As described above, the discharge power P3 of the inverter 120a-3 = 25/3 [kW], the discharge power P2 of the inverter 120a-2 = 25/3 [kW], and the discharge power P1 of the inverter 120a-1 = 25/3 [kW]. It was decided. At the start of discharge, the controller 110b causes the inverter 120a to execute a peak cut operation with discharge power (total) Pd = 25 [kW].

Control unit 110b periodically includes SOC1 of storage battery 140a-1 connected to inverter 120a-1, SOC2 of storage battery 140a-2 connected to inverter 120a-2, and storage battery 140a-3 connected to inverter 120a-3. SOC3 is received and the above determination is made.
Since 360% of the storage battery 140a-3 connected to the inverter 120a-3 is 40% after the elapse of 360 minutes from the start of discharge, the stored power amount of the storage battery 140-2 is 40 kWh. Since the SOC2 of the storage battery 140a-2 connected to the inverter 120a-2 is 40%, the stored power amount of the storage battery 140-2 is 40 kWh. Moreover, since SOC1 of the storage battery 140a-1 connected to the inverter 120a-1 is 40%, the stored power amount of the storage battery 140-1 is 40 kWh.
The discharge power P3 of the inverter 120a-3 = 25/3 [kW], the discharge power P2 of the inverter 120a-2 = 25/3 [kW], and the discharge power P1 of the inverter 120a-1 = 25/3 [kW]. Therefore, after 360 minutes have elapsed from the start of discharge, (storage battery 140-3 or storage battery 140-2 or storage battery 140-1 stored electric energy 40 [kWh]) ÷ 25/3 [kW] = 4.8 [h] ( 288 minutes), the SOC3 of the storage battery 140a-3 connected to the inverter 120a-3, the SOC2 of the storage battery 140a-2 connected to the inverter 120a-2, and the storage battery 140a-1 connected to the inverter 120a-1 SOC1 becomes equal.

After 648 minutes have elapsed from the start of discharge, SOC1 of inverter 120a-1, SOC2 of inverter 120a-2, and SOC3 of inverter 120a-3 are as follows.
40 kWh after 360 minutes from the start of discharge of the storage battery 140-3 was discharged for 4.8 hours at the discharge power P1 = 25/3 [kW], so 40 [kWh] -25/3 [kW] × Since 4.8 [h] = 0 [kWh], SOC3 = 0 [%]. The amount of stored power 40 kWh after the elapse of 360 minutes from the start of discharge of the storage battery 140-2 was discharged for 4.8 hours at a discharge power P2 = 25/3 [kW], so 40 [kWh] -25/3 [kW] × Since 4.8 [h] = 0 [kWh], SOC2 = 0 [%]. Since the storage power amount 40 kWh after the elapse of 360 minutes from the start of the discharge of the storage battery 140-1 was discharged for 4.8 hours at the discharge power P1 = 25/3 [kW], 40 [kWh] -25/3 [kW] × Since 4.8 [kW] = 0 [kWh], SOC1 = 0 [%].

  In this way, the amount of power stored in storage battery 140-1 to storage battery 140-3 of inverter 120a becomes 0 kWh simultaneously after 10.8 h (648 minutes) has elapsed since the start of peak cut operation. That is, the control unit 110b maintains the discharge power (total) Pd at 25 kW until the discharge is stopped by reviewing the discharge power P1 to P3 of the inverters 120a-1 to 120a-3 according to the flow shown in FIG. Therefore, it is possible to use the power (storage power amount) of the storage battery for peak cut without waste.

As described above, the control unit 110b includes the storage batteries (storage battery 130-1 to storage battery 130-3, storage battery 140-1 to storage battery 140-) connected to each of the plurality of power conversion units (inverters 120a-1 to 120a-3). 3) The higher the storage battery (storage battery 130-3, storage battery 140-3), the higher the discharge power, the higher the SOC, so that the SOC of each of the plurality of power conversion units is discharged.
With this configuration, the time until the SOC of the storage battery in each power conversion unit becomes 0% can be made the same, so the power of the storage battery can be used for peak cut operation without waste.

  As described above, the embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the scope of the present invention. It is possible to

  DESCRIPTION OF SYMBOLS 10, 10a, 10b ... Autonomous driving system, 110, 110a, 110b ... Control part, 120 ... Inverter, 130, 140 ... Storage battery, 150 ... Solar power generation device, 151 ... Solar cell, 152 ... Power conditioner, 160 ... Building Load 200 ... Power line 210 ... Power receiving point 400 ... Commercial system

Claims (3)

A distributed power supply autonomous operation system that reduces power from the commercial system,
A plurality of power conversion units that perform grid power compensation at a power receiving point of power from the commercial system using a storage battery in connection with the commercial system,
When the power at the power receiving point is equal to or higher than a preset target power value, a control unit that controls the plurality of power conversion units to discharge power from the storage battery;
With
The control unit controls the discharge power of each of the plurality of power conversion units according to the SOC of a storage battery connected to the plurality of power conversion units.
An autonomous operation system for distributed power sources. The control unit controls the discharge power of each of the plurality of power conversion units in proportion to the SOC of a storage battery connected to each of the plurality of power conversion units.
The autonomous operation system for a distributed power source according to claim 1. The control unit is configured such that a storage battery with a higher SOC has a higher discharge power so that the SOC of the storage battery connected to each of the plurality of power conversion units is equal, and discharges from each of the plurality of power conversion units.
The autonomous operation system for a distributed power source according to claim 1.

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