JP2019030160A - Distribution-type power supply system - Google Patents

Abstract

To provide a distribution-type power supply system including a charging/discharging device that is operated together with a power generation device and is capable of avoiding, while suppressing reduction in output of the power generation device, reduction in durability of a storage battery of the charging/discharging device caused by its full-charged state continuing for a long period of time.SOLUTION: A distribution-type power supply system includes a charge/discharge control unit 21 that in the case of being set to a first charging/discharging mode, controls reception power Pb received from an AC line 2 by a charging/discharging device 20 so that the sum of power consumption P3 received from the AC line 2 by a power consuming device 3 and the reception power Pb becomes equal to target power and shifts into a charging prohibition mode when a period in which a charged level of a charging/discharging unit 22 is equal to or higher than a first upper limit level has continued for a period equal to or longer than a predetermined period, and, in the case of being set in the charging prohibition mode, makes self consumption of power stored in the charging/discharging unit 22 be performed without the charging/discharging device 20 performing power charging from the AC line 2, until the charged level has reduced to be lower than a predetermined lower limit level lower than the first upper limit level.SELECTED DRAWING: Figure 1

Description

  The present invention includes an AC line connected to an electric power system, a power generation device connected to the AC line and having a power generation unit and a power generation control unit that controls the operation of the power generation unit, and connected to the AC line, A charge / discharge unit including a storage battery that performs charge / discharge of power between the battery and a charge / discharge device having a charge / discharge control unit that controls the operation of the charge / discharge unit, and the power consumption device is connected to the AC line The present invention relates to a distributed power system.

  Conventionally, an AC line connected to the power system, a power generator that can freely adjust the output, such as a fuel cell device connected to the AC line, and a charge / discharge device connected to the AC line, There is a distributed power supply system in which a power consuming device is connected to the AC line. In such a distributed power supply system, power can be supplied to the power consuming device from at least one of the power system, the power generation device, and the charge / discharge device. Therefore, power can be supplied to the power consuming device in a state where the power received from the power system is reduced by causing the power generation device to perform a power generation operation or discharging from the charge / discharge device.

  Patent Document 1 describes a distributed power supply system that does not include the above-described power generation device, but includes a solar power generation device and a storage battery (charge / discharge device). In this distributed power supply system, after the PV charging mode in which surplus power of the photovoltaic power generator is charged to the storage battery in the daytime, the storage battery is set so that the storage battery charge level: SOC (State of Charge) becomes a predetermined lower limit level. The forced discharge mode to be discharged is executed. Furthermore, after the forced discharge mode, a regression mode in which the storage battery is charged by external power at night is executed. With this PV charging mode, surplus power of the solar power generation device can be stored in the daytime, and with the subsequent forced discharge mode, the remaining capacity of the storage battery is ensured while leaving a minimum amount of power for backup, and further thereafter Regression mode can store nighttime power.

  In the distributed power supply system described in Patent Literature 1, the PV charge mode is executed only during a predetermined time zone (daytime) every day, and the PV charge mode is not executed during other time zones. Therefore, the SOC of the storage battery can be sufficiently reduced by the forced discharge mode executed after the daytime PV charging mode until the nighttime regression mode is executed.

JP 2016-220461 A

  Unlike the solar power generation apparatus provided in the distributed power supply system described in Patent Document 1, the power generation apparatus can generate power in any time zone. In addition, if the distributed power supply system includes a charging / discharging device, the power generation device is operated at a constant output regardless of the power consumption of the power consuming device, and the insufficient power is the discharging power from the storage battery of the charging / discharging device. Covering and surplus power can be efficiently operated by charging the storage battery of the charging / discharging device.

  However, in spring and autumn, there may be a continuous period in which the power consumption of the power consuming device is relatively smaller than in summer and winter when large power is consumed for cooling and heating. Therefore, when the power generation device is operated at a constant output and the surplus power is charged in the storage battery of the charge / discharge device, the charge level of the storage battery of the charge / discharge device hardly decreases, and in an extreme case, the charge level is almost 100%. The state may continue. As a result, for example, there is an increased possibility of adversely affecting the life (durability) of a storage battery such as a lithium ion battery.

  On the other hand, if the storage battery is forcibly discharged to eliminate the fully charged state of the storage battery, the output of the power generator must be reduced. Therefore, there is a problem that the energy saving property of the distributed power supply system is lowered.

  The present invention has been made in view of the above-mentioned problems, and the purpose of the present invention is to reduce the durability of the storage battery of the charge / discharge device due to the continuous full charge state for a long period of time for the charge / discharge device operated together with the power generation device. The object is to provide a distributed power supply system that can be avoided.

The characteristic configuration of the distributed power supply system according to the present invention for achieving the above object includes an AC line connected to a power system, and a power generation control connected to the AC line and controlling the operation of the power generation unit and the power generation unit. A charging / discharging control unit that controls operation of the charging / discharging unit and a charging / discharging unit including a storage battery that is connected to the AC line and performs charging / discharging of electric power to / from the AC line. A distributed power supply system comprising a charge / discharge device, wherein a power consuming device is connected to the AC line,
As the received power that the charging / discharging device receives from the AC line, the charging power from the AC line by the charging / discharging device is regarded as positive receiving power, and the discharging power to the AC line by the charging / discharging device is negative receiving When considering power
The power generation control unit of the power generation device generates power from the power generation device from the AC power line in accordance with a sum of power consumption received by the power consumption device from the AC line and power received by the charge / discharge device from the AC line. Controlling the power provided from the power generator to the AC line within a range between a predetermined minimum provided power and a maximum provided power,
The charge / discharge control unit of the charge / discharge device comprises:
When the operation mode is set to a first charging / discharging mode in which charging / discharging of power between the charging / discharging device and the AC line is permitted, the power consumption device receives power consumption from the AC line; The charge / discharge device receives the power received from the AC line so that the sum of the received power received from the AC line by the charge / discharge device becomes a predetermined target power,
When the operation mode is set to the first charge / discharge mode, the operation mode is changed to the charge prohibition mode when a period in which the charge level of the charge / discharge unit is equal to or higher than a predetermined first upper limit level continues for a predetermined period or longer. ,
When the operation mode is set to the charge prohibition mode, the charge / discharge device is configured to reduce the charge level of the charge / discharge unit to a level lower than a predetermined first lower limit level that is lower than the first upper limit level. There exists in the point comprised so that the self-consumption of the electric power stored in the said charging / discharging part may be performed, without charging the electric power from an AC line.

  According to the above characteristic configuration, when the operation mode is set to the first charge / discharge mode, the charge / discharge control unit of the charge / discharge device receives the power consumption that the power consuming device receives from the AC line, and the charge / discharge device is the AC line. The received power received from the AC line by the charging / discharging device is controlled so that the sum of the received power received from the power source and the received power becomes a predetermined target power. As a result, the power generation control unit of the power generation device provides power corresponding to the constant target power from the power generation device to the AC line while the operation mode of the charge / discharge device is set to the first charge / discharge mode. In addition, the power supplied from the power generator to the AC line is controlled. That is, while the operation mode of the charge / discharge device is set to the first charge / discharge mode, the power generation device can be preferably operated at a constant output (= target power).

When the operation mode of the charging / discharging device is set to the first charging / discharging mode, if the power consumption of the power consuming device continues below the target power, the charging / discharging control unit of the charging / discharging device It is necessary to continue charging the power from the AC line so that the sum of the power consumption of the consuming device and the received power of the charging / discharging device becomes the target power. In that case, the charge level of the charging / discharging unit may be fully charged or close to it, which may adversely affect the life (durability) of the storage battery.
Therefore, in this feature configuration, when the operation mode is set to the first charge / discharge mode, the charge / discharge control unit of the charge / discharge device has a predetermined period during which the charge level of the charge / discharge unit is equal to or higher than a predetermined first upper limit level. If it continues for a period or more, the operation mode is changed to the charge prohibition mode, and the charging / discharging device is disconnected from the AC line until the charging level of the charging / discharging unit decreases and falls below a predetermined first lower limit level that is lower than the first upper limit level. The self-consumption of the electric power stored in the charging / discharging unit is performed without charging the electric power. In other words, the charge / discharge control unit of the charge / discharge device operates in the charge prohibition mode, so that the life (durability) of the storage battery is adversely affected by the state where the charge level of the charge / discharge unit is fully charged or close to it. Can be prevented in advance. In addition, since the power is not forcibly discharged from the charging / discharging device to the AC line, power corresponding to the power consumption of the power consuming device can be provided from the power generating device to the AC line, and the output reduction of the power generating device is suppressed. Is done.
Accordingly, for a charging / discharging device that is operated together with a power generation device, a distributed power supply system that can prevent a decrease in durability of the storage battery of the charging / discharging device due to a continuous full charge state while suppressing a decrease in output of the power generation device is provided. it can.

  Another characteristic configuration of the distributed power supply system according to the present invention is that the charge / discharge control unit of the charge / discharge device has a reduced charge level of the charge / discharge unit when an operation mode is set to the charge prohibition mode. When the operation mode is changed to the second charge / discharge mode when the operation mode is set to the second charge / discharge mode, the charge level of the charge / discharge unit is set to the first charge level. In a state where charging / discharging of electric power with the AC line by the charging / discharging device is permitted on condition that the predetermined second upper limit level which is higher than the lower limit level and lower than the first upper limit level is not exceeded. Receipt received by the charge / discharge device from the AC line such that the sum of the power consumption received by the consumer device from the AC line and the received power received by the charge / discharge device from the AC line becomes the target power. There is a point to control the force.

According to the above characteristic configuration, when the charging level of the charging / discharging unit decreases and becomes lower than the first lower limit level while the charging / discharging device is operating in the charging prohibition mode, the operation mode is changed to the second charging / discharging mode. The target is the sum of the power consumption received by the power consuming device from the AC line and the power received by the charge / discharge device from the AC line while charging / discharging of power between the AC line and the charging / discharging device is permitted. The electric power received by the charging / discharging device from the AC line is controlled so as to become electric power. As a result, the power generation control unit of the power generation device controls the power supplied from the power generation device to the AC line so as to provide power corresponding to the certain target power from the power generation device to the AC line. That is, while the operation mode of the charging / discharging device is set to the second charging / discharging mode, the power generation device can be preferably operated at a constant output (= target power).
In addition, in this characteristic configuration, when the operation mode is set to the second charge / discharge mode, the charge level of the charge / discharge unit is higher than the first lower limit level and lower than the first upper limit level. On condition that it does not exceed, charging / discharging of electric power between the AC line by the charging / discharging device is permitted. That is, since the charge level of the charge / discharge unit is prevented from being higher than or equal to the second upper limit level (that is, higher than or equal to the first upper limit level). The problem of adversely affecting the life (durability) of the battery can be prevented.

  Still another characteristic configuration of the distributed power supply system according to the present invention is that the charge / discharge control unit of the charge / discharge device has an operation mode in which a charge level of the charge / discharge unit is higher than the first lower limit level and the first When the charging / discharging device is set to the second charging / discharging mode in which charging / discharging of power with the AC line is permitted on condition that a predetermined second upper limit level lower than one upper limit level is not exceeded. The reception received by the charge / discharge device from the AC line so that the sum of the power consumption received by the power consumption device from the AC line and the received power received by the charge / discharge device from the AC line becomes the target power. When the electric power is controlled and the operation mode is set to the second charge / discharge mode, the charge level of the charge / discharge unit decreases to be less than a predetermined second lower limit level that is less than the first lower limit level. Lies in changing the operation mode to the first charge and discharge mode.

According to the above characteristic configuration, the charge / discharge control unit of the charge / discharge device permits charging / discharging of power between the charge / discharge device and the AC line when the operation mode is set to the second charge / discharge mode. In this state, the power received by the charging / discharging device from the AC line is controlled so that the sum of the power consumption received by the power consuming device from the AC line and the power received by the charging / discharging device from the AC line becomes the target power. As a result, the power generation control unit of the power generation device controls the power supplied from the power generation device to the AC line so as to provide power corresponding to the certain target power from the power generation device to the AC line. That is, while the operation mode of the charging / discharging device is set to the second charging / discharging mode, the power generation device can be preferably operated at a constant output (= target power).
In addition, in this characteristic configuration, when the operation mode is set to the second charge / discharge mode, the charge level of the charge / discharge unit is higher than the first lower limit level and lower than the first upper limit level. On condition that it does not exceed, charging / discharging of electric power between the AC line by the charging / discharging device is permitted. That is, since the charge level of the charge / discharge unit is prevented from being higher than or equal to the second upper limit level (that is, higher than or equal to the first upper limit level). The problem of adversely affecting the life (durability) of the battery can be prevented.

  Furthermore, when the operation mode is set to the second charge / discharge mode, the charge / discharge control unit of the charge / discharge device has a predetermined second lower limit level in which the charge level of the charge / discharge unit decreases and is less than the first lower limit level. If it becomes less than this, the operation mode is changed to the first charge / discharge mode. That is, charging up to the first upper limit level is permitted in a state where the charging level of the charging / discharging unit is greatly reduced and the charging margin is increased. As a result, it can be avoided that the charging level of the charging / discharging unit is fully charged or close to that in a short period of time.

  Still another characteristic configuration of the distributed power supply system according to the present invention is that the charge / discharge control unit receives the power consumed by the power consuming device from the AC line when power is not supplied from the power generating device to the AC line. The power corresponding to the power is supplied from the charging / discharging device to the AC line.

  According to the above characteristic configuration, when power is not supplied from the power generation device to the AC line, power corresponding to the power consumption that the power consuming device receives from the AC line is supplied from the charging / discharging device to the AC line. As a result, even when power is not supplied from the power generation device to the AC line, the received power (that is, purchased power) from the power system can be reduced.

It is a figure which shows the structure of the distributed power supply system of 1st Embodiment. It is a flowchart explaining a mode setting process. It is a graph which shows the transition example of the charge level of a storage battery. It is a figure which shows the structure of the distributed power supply system of 2nd Embodiment.

<First Embodiment>
A distributed power supply system according to a first embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram illustrating a configuration of a distributed power supply system according to the first embodiment. As shown in FIG. 1, the distributed power supply system includes an AC line 2 connected to the power system 1, a fuel cell device 10 as a power generator connected to the AC line 2, and a charge connected to the AC line 2. A power consuming device 3 is connected to the AC line 2. Moreover, in this embodiment, the 1st connection location 6 and the 2nd connection location 7 are provided in the arrangement order toward the downstream side seeing from the connection location of the electric power system 1 with respect to the AC line 2, and the 1st connection location 6 Is connected to the fuel cell device 10, and the second connection location 7 is connected to the charge / discharge device 20 and the power consuming device 3. When the sum of the power supplied from the fuel cell device 10 to the AC line 2 and the power supplied from the charging / discharging device 20 to the AC line 2 is less than the power consumption P3 of the power consuming device 3, the insufficient power is supplied from the power system 1. Covered by received power.

  As shown in FIG. 1, in the present embodiment, the power P <b> 1 in the direction from the power system 1 to the first connection location 6 is regarded as positive power, and the power in the direction from the first connection location 6 to the second connection location 7. Consider P2 as positive power. Further, as the received power Pb received by the charging / discharging device 20 from the AC line 2, the charging power from the AC line 2 by the charging / discharging device 20 is regarded as positive received power, and the discharging power to the AC line 2 by the charging / discharging device 20 is The description will be made assuming that the received power is negative. Therefore, in FIG. 1, the received power Pb is indicated by an arrow in a direction from the AC line 2 toward the charge / discharge device 20.

[Fuel cell device 10]
The fuel cell device 10 as a power generation device includes a fuel cell unit 12 as a power generation unit and a fuel cell control unit 11 as a power generation control unit that controls the operation of the fuel cell unit 12. The fuel cell unit 12 includes a fuel cell 12a and a power conversion unit 12b that converts electric power generated in the fuel cell 12a into electric power having a desired voltage, frequency, and phase and outputs the electric power to the AC line 2.

  The fuel cell 12a can be realized using, for example, a solid oxide fuel cell (SOFC). Alternatively, the fuel cell 12a may be realized using another type of fuel cell such as a polymer electrolyte fuel cell (PEFC). In addition, although illustration is abbreviate | omitted, the fuel cell part 12 may be equipped with the fuel reformer etc. which produce | generate hydrogen etc. as fuel gas supplied to the anode of the fuel cell 12a by a reforming process. The fuel cell control unit 11 controls operation start, operation stop, output state, and the like of the fuel cell 12a. Further, the fuel cell control unit 11 controls the power conversion operation by the power conversion unit 12b.

  Information about the power measured by the power meter 4 is transmitted to the fuel cell control unit 11. The power measuring instrument 4 is provided on the upstream side (the power system 1 side) of the first connection location 6 in the middle of the AC line 2 and measures the power traveling from the power system 1 side to the first connection location 6. The power meter 4 is configured by using a current transformer (instrument current transformer) used for detecting the current value of power in the AC line 2, for example, and with a predetermined voltage value (for example, 100V, 200V, etc.). From the product, the power value in the AC line 2 can be derived. The power meter 4 may transmit only the current value of the power on the AC line 2 to the fuel cell control unit 11, and the fuel cell control unit 11 may derive the power value.

  The power P1 measured by the power meter 4 is determined from the sum of the power consumption P3 received by the power consuming device 3 from the AC line 2 and the received power Pb received by the charging / discharging device 20 from the AC line 2, and the AC from the fuel cell device 10. This corresponds to a value obtained by subtracting the power Pf provided to the line 2.

  The fuel cell control unit 11 of the fuel cell device 10 refers to the measurement result of the power meter 4, and the power consumption P3 received by the power consumption device 3 from the AC line 2 and the received power received by the charge / discharge device 20 from the AC line 2. In order to provide power corresponding to the sum of Pb from the fuel cell device 10 to the AC line 2, the fuel cell device 10 is connected to the AC line 2 within a range between a predetermined minimum provided power and maximum provided power. The provided power Pf is controlled. For example, the fuel cell device 10 is configured so that the power P1 from the power system 1 side toward the first connection point 6 is preferably not negative power and set power as small as possible (particularly preferably, the set power Is adjusted to zero, that is, the electric power P1 from the electric power system 1 side to the first connection point 6 becomes zero), and the electric power Pf provided from the fuel cell device 10 to the AC line 2 is adjusted.

[Charging / discharging device 20]
The charging / discharging device 20 includes a charging / discharging unit 22 including a storage battery 22 a that charges and discharges electric power to and from the AC line 2 and a charging / discharging control unit 21 that controls the operation of the charging / discharging unit 22. In addition, in the charging / discharging unit 22 of the present embodiment, the storage battery 22a is connected to the AC line 2 via the power conversion unit 22b. As a result, the charging / discharging unit 22 can convert the electric power stored in the storage battery 22 a into electric power having a desired voltage, frequency, and phase and output the electric power to the AC line 2. The storage battery 22a can be configured using a secondary battery such as a lithium ion battery. The charge / discharge control unit 21 controls the operation of the power conversion unit 22b to control the output power (discharge power) from the storage battery 22a to the AC line 2 and the input power (charge power) from the AC line 2 to the storage battery 22a. And control.

  Although not shown, the charging / discharging device 20 includes, for example, a display device, an arithmetic processing device, a semiconductor element, a cooling fan, or the like as a device that can consume power when the power is turned on and the inside is energized. I have. Therefore, the charging / discharging device 20 can also change the power consumed by the device itself by adjusting the energization amount to these devices.

  Information about the power measured by the power meter 5 is transmitted to the charge / discharge control unit 21. In the present embodiment, the power meter 5 is provided between the first connection location 6 and the second connection location 7 in the middle of the AC line 2, and the power is directed from the first connection location 6 to the second connection location 7. Measure. That is, the power measured by the power meter 5 corresponds to the sum of the power consumption P3 received by the power consumption device 3 from the AC line 2 and the power reception Pb received by the charge / discharge device 20 from the AC line 2. The power meter 5 is configured by using a current transformer (instrument current transformer) used for detecting the current value of power in the AC line 2, for example, and with a predetermined voltage value (for example, 100V, 200V, etc.). From the product, the power value in the AC line 2 can be derived. The power meter 5 may transmit only the current value of the power on the AC line 2 to the charge / discharge control unit 21, and the charge / discharge control unit 21 may derive the power value. Then, the charge / discharge control unit 21 refers to the measurement result of the power meter 5 and controls the received power Pb received by the charge / discharge device 20 from the AC line 2.

  The charge / discharge control unit 21 of the charge / discharge device 20 sets one of a plurality of operation modes, and controls received power Pb received by the charge / discharge device 20 from the AC line 2 in the set operation mode. In the present embodiment, the plurality of operation modes include a first charge / discharge mode, a second charge / discharge mode, and a charge prohibition mode as described later.

The first charging / discharging mode is an operation mode in which charging / discharging of power between the charging / discharging device 20 and the AC line 2 is permitted. When the operation mode is set to the first charge / discharge mode, the charge / discharge control unit 21 of the charge / discharge device 20 includes the power consumption P3 that the power consumption device 3 receives from the AC line 2, and the charge / discharge device 20 is the AC line 2 The charging / discharging device 20 controls the received power Pb received from the AC line 2 so that the sum of the received power Pb received from the AC and the received power Pb becomes a predetermined target power. For example, the target power is set to a value equal to the rated generated power of the fuel cell device 10, for example.
In addition, when the operation mode is set to the first charge / discharge mode, the charge / discharge control unit 21 of the charge / discharge device 20 has a charge level of the charge / discharge unit 22: SOC (State of Charge) is a predetermined first upper limit. When the period equal to or higher than the level continues for a predetermined period or longer, the operation mode is changed to the charge prohibition mode.

The charge prohibition mode is an operation mode when the charging / discharging device 20 performs self-consumption of the electric power stored in the charging / discharging unit 22 without charging the electric power from the AC line 2. When the operation mode is set to the charge prohibition mode, the charge / discharge control unit 21 of the charge / discharge device 20 is less than a predetermined first lower limit level that is lower than the first upper limit level due to a decrease in the charge level of the charge / discharge unit 22. Until it becomes, the charging / discharging device 20 performs the self-consumption of the electric power stored in the charging / discharging unit 22 without charging the electric power from the AC line 2. At this time, the charging / discharging control unit 21 of the charging / discharging device 20 may increase the self-consumed power while the charging prohibiting mode is set as compared with the case where the charging prohibiting mode is not set. For example, the charging / discharging control unit 21 of the charging / discharging device 20 may perform control such as increasing power consumption of a display device, a cooling fan, or the like included in the charging / discharging device 20 while the charging prohibition mode is set. Good.
In addition, when the operation mode is set to the charge prohibition mode, the charge / discharge control unit 21 of the charge / discharge device 20 changes the operation mode when the charge level of the charge / discharge unit 22 decreases and becomes lower than the first lower limit level. Change to the second charge / discharge mode.

In the second charge / discharge mode, the AC line 2 by the charge / discharge device 20 is provided on the condition that the charge level of the charge / discharge unit 22 does not exceed a predetermined second upper limit level that is higher than the first lower limit level and lower than the first upper limit level. It is an operation mode in which charging / discharging of electric power is permitted. When the operation mode is set to the second charge / discharge mode, the charge / discharge control unit 21 of the charge / discharge device 20 has a predetermined charge level that is higher than the first lower limit level and lower than the first upper limit level. Power consumption P3 received from the AC line 2 by the power consuming apparatus 3 in a state where charging / discharging of power between the AC line 2 by the charging / discharging apparatus 20 is permitted on condition that the second upper limit level is not exceeded, and charging / discharging The received power Pb received by the charge / discharge device 20 from the AC line 2 is controlled so that the sum of the received power Pb received by the discharge device 20 from the AC line 2 becomes the target power.
In addition, when the operation mode is set to the second charge / discharge mode, the charge / discharge control unit 21 of the charge / discharge device 20 has a predetermined charge level of the charge / discharge unit 22 that is lower than the first lower limit level. When it becomes less than the second lower limit level, the operation mode is changed to the first charge / discharge mode.

  Next, an operation mode setting process of the charge / discharge device 20 will be described with reference to FIGS. FIG. 2 is a flowchart for explaining the mode setting process. FIG. 3 is a graph showing a transition example of the charge level of the storage battery 22a: SOC (State of Charge).

  The charge / discharge control unit 21 of the charge / discharge device 20 controls the received power Pb received from the AC line 2 by the charge / discharge device 20 as described above while performing the mode setting process shown in FIG. As described above, as the received power Pb received by the charging / discharging device 20 from the AC line 2, the charging power from the AC line 2 by the charging / discharging device 20 is regarded as positive received power, and the AC line 2 by the charging / discharging device 20 is used. Is regarded as negative received power.

In step # 10, the charge / discharge control unit 21 determines whether or not the current operation mode is the charge prohibition mode. If the current mode is the charge prohibition mode, the process proceeds to step # 14. Shifts to step # 11.
Next, in step # 11, the charge / discharge control unit 21 determines whether or not the current operation mode is the first charge / discharge mode. If the current operation mode is the first charge / discharge mode, the process proceeds to step # 12. When it is not the first charge / discharge mode (that is, the second charge / discharge mode), the process proceeds to step # 16.
As described above, in Step # 10 and Step # 11, it is determined whether the current operation mode is the first charge / discharge mode, the second charge / discharge mode, or the charge prohibition mode. The

  In step # 12, the charge / discharge control unit 21 determines whether or not the period during which the charge level of the charge / discharge unit 22 is equal to or higher than the first upper limit level continues for a predetermined period or longer, and the period continues for a predetermined period or longer. In this case, the process proceeds to step # 13. On the other hand, when the period has not continued for a predetermined period or longer, the charge / discharge control unit 21 returns to the beginning of this flowchart while maintaining the first charge / discharge mode.

  In the example shown in FIG. 3, the charging level of the charging / discharging unit 22 becomes equal to or higher than the first upper limit level (H1) at time t1, and the charging / discharging control unit 21 determines that the charging level of the charging / discharging unit 22 is the first level at time t2. It is determined that a period of one upper limit level or more has continued for a predetermined period or more (determined as “Yes” in step # 12). As a specific example, in spring and autumn, the period in which the power consumption P3 of the power consuming apparatus 3 is relatively smaller than that in the summer and winter when large power is consumed for cooling and heating continues. There is. In this case, the charging / discharging device 20 charges the power from the AC line 2, whereby the power consumption device 3 receives the power consumption P <b> 3 received from the AC line 2 and the charging / discharging device 20 receives the received power Pb from the AC line 2. The received power Pb received from the AC line 2 by the charging / discharging device 20 is controlled so that the sum of the two becomes the target power. That is, since the charging / discharging device 20 continues to be charged so that the fuel cell device 10 can be operated with a constant supply power Pf (= target power), the charge level is decreased as shown in FIG. It will increase monotonously.

  Next, in step # 13, the charging / discharging device 20 sets the operation mode to the charge inhibition mode. The charging / discharging control unit 21 causes the charging / discharging device 20 to be connected to the AC line 2 until the charging level of the charging / discharging unit 22 decreases and falls below a predetermined first lower limit level (release threshold) that is lower than the first upper limit level. The self-consumption of the electric power stored in the charging / discharging unit 22 is performed without charging the electric power from. As a result, the charge level of the charge / discharge unit 22 decreases. That is, the charging / discharging control unit 21 of the charging / discharging device 20 operates in the charge prohibition mode, so that the charge level of the charging / discharging unit 22 is fully charged or is in a state close thereto. Problems such as adverse effects can be prevented in advance. In addition, since the power is not forcibly discharged from the charging / discharging device 20 to the AC line 2, the power corresponding to the power consumption P <b> 3 of the power consumption device 3 can be provided from the fuel cell device 10 to the AC line 2, The output reduction of the fuel cell device 10 is suppressed.

  In the example shown in FIG. 3, the charging level of the charging / discharging unit 22 monotonously decreases after the charging inhibition mode is set at time t <b> 2. And the charging / discharging control part 21 determines with the charge level of the charging / discharging part 22 falling and becoming less than the 1st minimum level (L1) in time t3 (it determines with "Yes" by process # 14).

  Next, in step # 15, the charge / discharge control unit 21 sets the operation mode to the second charge / discharge mode. When the operation mode is set to the second charge / discharge mode, the charge / discharge control unit 21 has a predetermined second upper limit in which the charge level of the charge / discharge unit 22 is higher than the first lower limit level and lower than the first upper limit level. The power consumption P3 received by the power consuming device 3 from the AC line 2 and the charging / discharging device 20 in a state in which charging / discharging of power between the AC line 2 by the charging / discharging device 20 is permitted on condition that the level is not exceeded. The charge / discharge device 20 controls the received power Pb received from the AC line 2 so that the sum of the received power Pb received from the AC line 2 becomes the target power. Also in this case, the fuel cell control unit 11 of the fuel cell device 10 supplies the power corresponding to the certain target power from the fuel cell device 10 to the AC line 2 from the fuel cell device 10 to the AC line 2. The provided power Pf is controlled. That is, while the operation mode of the charging / discharging device 20 is set to the second charging / discharging mode, the fuel cell device 10 can be preferably operated at a constant output (= target power). In addition, since the charging level of the charging / discharging unit 22 is prevented from being higher than or equal to the second upper limit level (that is, higher than or equal to the first upper limit level), the charging level of the charging / discharging unit 22 continues at or near full charge. Thus, it is possible to prevent a problem that the life (durability) of the storage battery 22a is adversely affected.

  In step # 16, the charge / discharge control unit 21 is a predetermined second lower limit that is lower than the first lower limit level when the charge mode of the charge / discharge unit 22 is lowered in a state where the operation mode is set to the second charge / discharge mode. It is determined whether or not it has become less than the level (L2). If the charge level of the charge / discharge unit 22 has become less than the second lower limit level (L2), the process proceeds to step # 17. On the other hand, when the charge level of the charge / discharge unit 22 is not less than the second lower limit level (L2), the charge / discharge control unit 21 returns to the beginning of this flowchart while maintaining the second charge / discharge mode. To do.

  In the example illustrated in FIG. 3, after being set to the second charge / discharge mode at time t <b> 3, the charge / discharge control unit 21 is provided on the condition that the charge level of the charge / discharge unit 22 does not exceed the second upper limit level (H2). The received power Pb received by the charging / discharging device 20 from the AC line 2 is controlled in a state where charging / discharging of the electric power between the charging / discharging device 20 and the AC line 2 is permitted. And the charging / discharging control part 21 determines with the charge level of the charging / discharging part 22 having become less than the 2nd lower limit level (L2) in time t4 (it determines with "Yes" by process # 16). As described above, when the operation mode is set to the second charge / discharge mode, the charge / discharge control unit 21 of the charge / discharge device 20 decreases the charge level of the charge / discharge unit 22 and is less than the second lower limit level (L2). Until it becomes, the upper limit (2nd upper limit level (H2)) is provided in the charge level. That is, charging up to the first upper limit level (H1) is permitted only when the charging level of the charging / discharging unit 22 is greatly reduced and the charging margin is increased. As a result, it can be avoided that the charge level of the charge / discharge unit 22 is fully charged or close to that state in a short period of time.

  In step # 17, the charge / discharge control unit 21 sets the operation mode to the first charge / discharge mode. The charge / discharge control unit 21 receives the power consumption P3 received by the power consumption device 3 from the AC line 2 and the reception received by the charge / discharge device 20 from the AC line 2 while the operation mode is set to the first charge / discharge mode. The received power Pb received from the AC line 2 by the charge / discharge device 20 is controlled so that the sum of the power Pb and the predetermined target power is obtained. Therefore, the fuel cell control unit 11 of the fuel cell device 10 supplies power corresponding to the constant target power from the fuel cell device 10 while the operation mode of the charge / discharge device 20 is set to the first charge / discharge mode. The provided power Pf from the fuel cell device 10 to the AC line 2 is controlled so as to be provided to the AC line 2. That is, while the operation mode of the charge / discharge device 20 is set to the first charge / discharge mode, the fuel cell device 10 can be operated preferably at a constant output (= target power).

Second Embodiment
In the distributed power supply system of the second embodiment, the operation of the charge / discharge control unit is different from that of the above embodiment. Although the distributed power supply system of 2nd Embodiment is demonstrated below, description is abbreviate | omitted about the content similar to 1st Embodiment.

  FIG. 4 is a diagram illustrating a configuration of a distributed power supply system according to the second embodiment. As shown in FIG. 4, the power meter 8 is provided at a position where the power (provided power Pf) supplied from the fuel cell device 10 to the AC line 2 can be measured. Information about the power measured by the power meter 8 is transmitted to the charge / discharge device 20. The power measuring instrument 8 is configured using a current transformer (instrument current transformer) used for detecting a current value of power in a connection line between the fuel cell device 10 and the AC line 2, for example, and has a predetermined voltage value. The power value at the connection line can be derived from the product with (for example, 100 V, 200 V, etc.). Therefore, the charging / discharging device 20 determines that the power is not supplied from the fuel cell device 10 to the AC line 2 if the power supplied from the fuel cell device 10 to the AC line 2 is equal to or lower than a lower threshold (for example, zero). If it is greater than the lower threshold, it can be determined that power is being supplied from the fuel cell device 10 to the AC line 2.

Then, the charging / discharging control unit 21 supplies power corresponding to the power consumption P3 received by the power consuming device 3 from the AC line 2 when the power is not supplied from the fuel cell device 10 to the AC line 2 due to reasons such as stopping. It is supplied to the AC line 2 from the charging / discharging device 20.
On the other hand, when the power is supplied from the fuel cell device 10 to the AC line 2, the charge / discharge control unit 21 performs the first charge / discharge mode and the second charge / discharge as described in the first embodiment. It operates in one of the operation modes of the mode and the charge prohibition mode.

  Thus, in the present embodiment, when power is not supplied from the fuel cell device 10 to the AC line 2, the power corresponding to the power consumption P <b> 3 received by the power consumption device 3 from the AC line 2 is exchanged from the charging / discharging device 20. Supplied to line 2. As a result, even when power is not supplied from the fuel cell device 10 to the AC line 2, the received power P <b> 1 (that is, purchased power) from the power system 1 can be reduced.

<Another embodiment>
<1>
In the above embodiment, the configuration of the distributed power supply system of the present invention has been described with a specific example, but the configuration can be changed as appropriate.
For example, the configurations of the fuel cell device 10 and the charge / discharge device 20 are not limited to those illustrated, and can be changed as appropriate.

  Moreover, in the said embodiment, the connection location of the fuel cell apparatus 10 and the charging / discharging apparatus 20 with respect to the alternating current line 2 can be changed suitably. For example, in the said embodiment, the fuel cell apparatus 10 is connected to the 1st connection location 6 of the upstream (the side close | similar to the electric power grid | system 1) of the alternating current line 2, and the charging / discharging apparatus 20 is the 2nd downstream of the alternating current line 2. Although the example connected to the connection location 7 was demonstrated, you may employ | adopt the connection aspect of connecting the fuel cell apparatus 10 to the AC line 2 downstream from the connection location of the charging / discharging apparatus 20 with respect to the AC line 2. FIG. Whatever connection mode is adopted, the fuel cell control unit 11 of the fuel cell device 10 refers to the power value measured at an appropriate location, and the power consumption P3 received by the power consumption device 3 from the AC line 2. Power supply Pf from the fuel cell device 10 to the AC line 2 is provided so that the power corresponding to the sum of the received power Pb received from the AC line 2 by the charging / discharging device 20 is provided from the fuel cell device 10 to the AC line 2. Control is sufficient. Similarly, the charge / discharge control unit 21 of the charge / discharge device 20 refers to the power value measured at an appropriate location, and when the operation mode is set to the first charge / discharge mode and the second charge / discharge mode, The charge / discharge device 20 is connected to the AC line 2 so that the sum of the power consumption P3 received by the power consumption device 3 from the AC line 2 and the received power Pb received by the charge / discharge device 20 from the AC line 2 becomes a predetermined target power. The received power Pb to be received may be controlled.

<2>
In the said embodiment, although the charge / discharge control part 21 demonstrated the example which operate | moves in the operation mode in any one of 1st charge / discharge mode, 2nd charge / discharge mode, and charge prohibition mode, for example, 2nd charge / discharge mode is carried out. Instead, the operation may be changed so that the operation is performed in any one of the first charge / discharge mode and the charge prohibition mode. To give a specific example, the charge / discharge control unit 21 of the charge / discharge device 20 performs charge / discharge without charging the power from the AC line 2 when the operation mode is set to the charge prohibition mode. When the charge level of the charging / discharging unit 22 is lowered by performing self-consumption of the electric power stored in the unit 22 and becomes lower than a predetermined lower limit level, the operation mode may be changed to the charge prohibition mode.

<3>
In the said embodiment, the charge / discharge control part 21 of the charging / discharging apparatus 20 is not charged with the electric power from the AC line 2, but is stored in the charging / discharging part 22 when the operation mode is set to charge prohibition mode. Although the description has been given of the self-consumption of power, the power may be discharged from the charging / discharging device 20 to the AC line 2 under a predetermined condition.
Specifically, when the power measured by the power meter 5 exceeds the target power, the charge / discharge control unit 21 of the charge / discharge device 20 determines that the power measured by the power meter 5 is equal to or lower than the target power. It is also possible to discharge power from the charging / discharging device 20 to the AC line 2 on the condition that it does not become. For example, when the target power is set to a value equal to the rated generated power of the fuel cell device 10, if the power measured by the power meter 5 exceeds the target power, the surplus power is increased by the fuel cell device 10. Cannot be supplied from the power system 1 and receives power from the power system 1. Therefore, the surplus power, that is, the power that cannot be supplied from the fuel cell device 10 may be supplied by discharging from the charge / discharge device 20 to the AC line 2.

<4>
In the above embodiment, the fuel cell device 10 is described as an example of the power generation device of the present invention, but various other power generation devices that can freely adjust the output within a range between a predetermined minimum provided power and a maximum provided power. Can be used. For example, it is possible to use a type of power generator configured to include an engine and a generator driven by the engine.

<5>
The configurations disclosed in the above-described embodiments (including other embodiments, the same applies hereinafter) can be applied in combination with the configurations disclosed in the other embodiments as long as no contradiction arises, and are disclosed in this specification. The embodiment is an exemplification, and the embodiment of the present invention is not limited to this, and can be appropriately modified without departing from the object of the present invention.

  The present invention relates to a charging / discharging device that operates together with a power generation device, and is capable of avoiding a decrease in durability of the storage battery of the charging / discharging device due to a continuous full charge state while suppressing a decrease in output of the power generation device. Available to:

1 Power System 2 AC Line 3 Power Consumption Device 10 Fuel Cell Device (Power Generation Device)
11 Fuel cell control unit (power generation control unit)
12 Fuel cell section (power generation section)
20 Charging / Discharging Device 21 Charging / Discharging Control Unit 22 Charging / Discharging Unit 22a Storage Battery P3 Power Consumption Pb Received Power Pf Provided Power

Claims (4)

AC line connected to the power system,
A power generation device connected to the AC line and having a power generation control unit that controls the operation of the power generation unit and the power generation unit;
A charging / discharging device including a charging / discharging unit including a storage battery connected to the AC line and charging / discharging electric power to / from the AC line, and a charging / discharging control unit for controlling the operation of the charging / discharging unit;
A distributed power supply system in which a power consuming device is connected to the AC line,
As the received power that the charging / discharging device receives from the AC line, the charging power from the AC line by the charging / discharging device is regarded as positive receiving power, and the discharging power to the AC line by the charging / discharging device is negative receiving When considering power
The power generation control unit of the power generation device generates power from the power generation device from the AC power line in accordance with a sum of power consumption received by the power consumption device from the AC line and power received by the charge / discharge device from the AC line. Controlling the power provided from the power generator to the AC line within a range between a predetermined minimum provided power and a maximum provided power,
The charge / discharge control unit of the charge / discharge device comprises:
When the operation mode is set to a first charging / discharging mode in which charging / discharging of power between the charging / discharging device and the AC line is permitted, the power consumption device receives power consumption from the AC line; The charge / discharge device receives the power received from the AC line so that the sum of the received power received from the AC line by the charge / discharge device becomes a predetermined target power,
When the operation mode is set to the first charge / discharge mode, the operation mode is changed to the charge prohibition mode when a period in which the charge level of the charge / discharge unit is equal to or higher than a predetermined first upper limit level continues for a predetermined period or longer. ,
When the operation mode is set to the charge prohibition mode, the charge / discharge device is configured to reduce the charge level of the charge / discharge unit to a level lower than a predetermined first lower limit level that is lower than the first upper limit level. A distributed power supply system configured to perform self-consumption of power stored in the charge / discharge unit without charging power from an AC line. The charge / discharge control unit of the charge / discharge device comprises:
When the operation mode is set to the charge prohibition mode, when the charge level of the charge / discharge unit decreases and becomes less than the first lower limit level, the operation mode is changed to the second charge / discharge mode,
When the operation mode is set to the second charge / discharge mode, the charge level of the charge / discharge unit does not exceed a predetermined second upper limit level that is higher than the first lower limit level and lower than the first upper limit level. Power consumption received by the power consuming device from the AC line, and reception received by the charge / discharge device from the AC line in a state where charging / discharging of power between the AC line and the charging / discharging device is permitted as a condition The distributed power supply system according to claim 1, wherein received power received by the charging / discharging device from the AC line is controlled so that a sum with electric power becomes the target electric power. The charge / discharge control unit of the charge / discharge device comprises:
With the AC line by the charging / discharging device, the operation mode is such that a charging level of the charging / discharging unit does not exceed a predetermined second upper limit level that is higher than the first lower limit level and lower than the first upper limit level. Power consumption received by the power consuming device from the AC line, and received power received by the charge / discharge device from the AC line. The received power received from the AC line by the charging / discharging device so that the sum of
When the operation mode is set to the second charge / discharge mode, when the charge level of the charge / discharge unit decreases and becomes less than a predetermined second lower limit level that is less than the first lower limit level, the operation mode is changed to the first mode. The distributed power supply system according to claim 1 or 2, which is changed to a single charge / discharge mode.   The charging / discharging control unit supplies power from the charging / discharging device to the AC line according to power consumption received from the AC line by the power consuming device when power is not supplied from the power generation device to the AC line. The distributed power supply system according to any one of claims 1 to 3.

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