JP7580324B2 - Fuel cell device, fuel cell system, and power supply management system - Google Patents

Description

The present invention relates to a fuel cell device, a fuel cell system , and a power supply management system that include a fuel cell unit that is connected to a power line that is connected to a power grid, and a control unit that controls the operation of the fuel cell unit.

In addition to conventional large-scale power plants, fuel cell devices installed in facilities such as homes and offices are also connected to the power system. Power load devices installed in the facilities are also connected to the power system. Using the fuel cell device and the power load device to increase or decrease the power at the receiving point of the facility can contribute to adjusting the balance of power supply and demand in the power system. In recent years, under the concept of a virtual power plant (VPP), attempts have been made to provide functions equivalent to those of a power plant by controlling the operation of consumer-side energy resources such as the above-mentioned fuel cell device and power load device installed in the consumer's facility. Note that the receiving point power of a facility includes both the power received from the power system to the facility and the reverse flow power from the facility to the power system.

The load power of the power load device installed in the facility can change suddenly depending on the on/off switching of the device and the usage status of the device. Therefore, if the facility's power receiving point power is to be adjusted to a desired value, the output power of the fuel cell device installed in the facility needs to follow the changes in the load power of the power load device.

Patent Document 1 (JP Patent Publication No. 2006-333563) describes a technology for making the output power of a power supply device follow changes in the load power of a power load device. This patent document 1 describes a control method for performing load following operation by combining multiple distributed power sources. Specifically, the control method describes a method for performing load following operation using multiple distributed power sources with different load following response characteristics, in which long-period load fluctuations to be followed are followed by an engine generator, short-period load fluctuations are followed by a power storage device, and steep load fluctuations that the power storage device cannot follow are compensated for by an electric double layer capacitor.

As another technique, Patent Document 2 (JP 2020-89087 A) describes a technique in which a power management device issues control commands to a facility equipped with power generation equipment, etc., every five minutes, causing the power generation equipment, etc., to output a fixed amount of power for those five minutes.

JP 2006-333563 A JP 2020-89087 A

The technology described in Patent Document 1 uses multiple power supply devices with different load following response characteristics, and is not applicable when using only a single power supply device. In addition, when a fuel cell device is used as a power supply device, there is a problem that the device will deteriorate if its output power is suddenly changed in response to fluctuations in the load power.

The invention described in Patent Document 2 keeps the output power constant for five minutes, so if a deviation occurs between the actual load power and the predicted load power during that time, there is a problem that the facility's receiving point power may not be accurately adjusted to the desired value.

The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a fuel cell device , a fuel cell system , and a power supply management system that can contribute to providing appropriate adjustment power while suppressing deterioration of the device.

A characteristic configuration of a fuel cell device according to the present invention for achieving the above object is a fuel cell device including a fuel cell unit connected to a power line that is connected to a power grid, and a control unit that controls an operation of the fuel cell unit,
The control unit is configured to set a target output value of the output power to be supplied from the fuel cell unit to the power line for each of multiple control timings included in a specified control period, to a value determined based on the predicted load power of a power load device connected to the power line, the target output value of the fuel cell unit set at one control timing is configured not to be changed for an individual control period until the next control timing, and if the actual load power of the power load device during an individual control period deviates from the predicted load power during that individual control period, the target output value of the fuel cell unit for the next individual control period is changed in accordance with the amount of deviation.
A characteristic configuration of a power supply management system according to the present invention for achieving the above object includes the fuel cell device installed in each of a plurality of facilities and capable of outputting electric power, and a management device capable of communicating with the plurality of fuel cell devices from outside the facilities,
the management device receives an electric power supply command for the control period determined by the electric power transaction from an aggregation coordinator that conducts electric power transactions in the electric power trading market, and transmits output control commands to the plurality of fuel cell devices that determine the output power of the fuel cell devices to be installed in each of the plurality of facilities, determined based on the supply command;
The fuel cell device determines the target output value based on the output control command received from the management device.

According to the above characteristic configuration, the control unit does not change the target output value of the fuel cell unit set at one control timing during the individual control period until the next control timing, thereby preventing the output power of the fuel cell unit from being frequently changed.
Furthermore, when the actual load power of the power load device during an individual control period deviates from the predicted load power during that individual control period, the control unit changes the target output value of the fuel cell unit during the next individual control period according to the deviation, so that the amount of power supplied from the fuel cell device to the power grid during a control period consisting of multiple individual control periods can be brought closer to the desired amount of power.
Therefore, it is possible to provide a fuel cell device that can contribute to providing an appropriate adjustment power while suppressing deterioration of the device , and a power supply management system that includes the fuel cell device .

Another characteristic configuration of the fuel cell device according to the present invention is that, when a deviation occurs in which the actual load power of the power load device during the individual control period is greater than the predicted load power during the individual control period, the control unit increases the target output value of the fuel cell unit during the next individual control period by the increase in the deviation, and, when a deviation occurs in which the actual load power of the power load device during the individual control period is smaller than the predicted load power during the individual control period, the control unit decreases the target output value of the fuel cell unit during the next individual control period by the decrease in the deviation.

According to the above characteristic configuration, even if the actual load power of the power load device during an individual control period deviates larger or smaller than the predicted load power during that individual control period, the amount of power supplied from the fuel cell device to the power system during the control period consisting of multiple individual control periods can be brought closer to the desired amount of power.

Another characteristic feature of the fuel cell device according to the present invention is that the control unit shortens the length of the individual control period as the deviation increases.

According to the above characteristic configuration, the target output value is increased or decreased in response to the deviation at shorter time intervals as the deviation becomes larger. As a result, operation is prevented from continuing without the target output value being increased or decreased, i.e., without any measures being taken to reduce the deviation.

A characteristic feature of the fuel cell system according to the present invention for achieving the above object is that a plurality of the fuel cell devices are connected to the power grid.
Here, the control timing may be set for each of the plurality of fuel cell devices.

The above characteristic configuration allows multiple fuel cell devices connected to a power grid to contribute to the provision of appropriate adjustment power.

FIG. 2 is a diagram showing the relationship between facilities, a management device, and an aggregation coordinator. FIG. 1 is a diagram showing an example of a facility configuration. FIG. 13 is a diagram illustrating an example of a target output value in a control period. FIG. 13 is a diagram illustrating an example of a target output value in a control period. FIG. 13 is a diagram illustrating an example of a target output value in a control period.

Figure 1 shows the relationship between a facility 20 in which a fuel cell device 10 and a power load device 4 are installed, a management device 30, and an aggregation coordinator 40. Figure 2 shows an example of the configuration of a facility 20. The power management system includes a fuel cell device 10 that is installed in each of a plurality of facilities 20 and capable of outputting power, and a management device 30 that can communicate with the plurality of fuel cell devices 10 from a remote location outside the facility 20. Note that the number of management devices 30 and the number of facilities 20 shown in Figure 1 can be changed as appropriate.

The management device 30 is also called a resource aggregator, and is an operator that controls the consumer-side energy resources by transmitting control information to the fuel cell device 10 and the power load device 4 as consumer-side energy resources to the facility 20 that has concluded a VPP (Virtual Power Plant) service contract. The aggregation coordinator 40 is an operator that bundles the amount of power controlled by each management device 30 and trades power with general electricity transmission and distribution operators and retail electricity operators in the electricity trading market, etc.

The management device 30 sequentially collects and stores power information such as the output power of the fuel cell device 10, the load power of the power load device 4, and the power receiving point power at the facility 20 from multiple facilities 20. In this embodiment, the term "load power of the power load device 4" refers to the total load power of all the power load devices 4 installed in the facility 20. The management device 30 predicts the power that can be supplied from each facility 20 in a specified future time period and transmits it to the aggregation coordinator 40. This supplyable power is an adjustment margin such as the ability to increase or decrease the power receiving point power of the facility 20. In this embodiment, "increasing the power receiving point power" means increasing the power received from the power system 1 to the power line 2, or decreasing the reverse flow power from the power line 2 to the power system 1, and "reducing the power receiving point power" means decreasing the power received from the power system 1 to the power line 2, or increasing the reverse flow power from the power line 2 to the power system 1.

For example, in order to increase the receiving point power of the facility 20, it is sufficient to at least either reduce the output power of the fuel cell device 10 or increase the load power of the power load device 4. Therefore, the increase-side adjustment margin when increasing the receiving point power of the facility 20 indicates how much margin there is for reducing the output power of the fuel cell device 10 and how much margin there is for increasing the load power of the power load device 4. Also, in order to decrease the receiving point power of the facility 20, it is sufficient to at least either increase the output power of the fuel cell device 10 or reduce the load power of the power load device 4. Therefore, the decrease-side adjustment margin when decreasing the receiving point power of the facility 20 indicates how much margin there is for increasing the output power of the fuel cell device 10 and how much margin there is for decreasing the load power of the power load device 4.

The management device 30 also determines the baseline power receiving point power for the multiple facilities 20 that it manages. This baseline power receiving point power corresponds to the total power receiving point power of each facility 20 predicted when each facility 20 is not allowed to provide adjustment capacity, etc. (i.e., adjustment capacity provided to the electricity transmission and distribution company and supply capacity provided to retailers, etc.).

The aggregation coordinator 40 aggregates the available electricity received from each management device 30 and trades electricity with general electricity transmission and distribution companies and retail electricity suppliers by bidding on electricity trading markets such as the supply and demand adjustment market, the wholesale electricity market, and the capacity market. When the aggregation coordinator 40 receives a supply command for adjustment capacity, etc. for a specified future control period from the general electricity transmission and distribution company or retail electricity supplier with which it has traded, it distributes and transmits the adjustment capacity, etc. specified in the supply command to each management device 30.

When the management device 30 receives a supply command from the aggregation coordinator 40, it distributes and transmits the adjustment power, etc. specified in the supply command to each facility 20. As a result, in each facility 20, the fuel cell device 10 and the power load device 4 as consumer-side energy resources are controlled during a specified future control period, and adjustment power, etc. is supplied such that the receiving point power of the facility 20 increases or decreases compared to the case where the control is not performed.

The facility 20 is equipped with a fuel cell device 10 and a power load device 4. The fuel cell device 10 and the power load device 4 are connected to a power line 2 that is linked to the power system 1. A power meter 3 that measures the power at the receiving point of the facility 20 is installed on the power line 2. Note that while Figures 1 and 2 show an example in which one fuel cell device 10 is installed, the number of fuel cell devices 10 installed can be changed as appropriate.

Information about the receiving point power measured by the power meter 3 is transmitted to the management device 30 via the gateway 5 and the router 6. For example, information about the receiving point power is transmitted to the management device 30 at a predetermined timing, such as every 10 seconds.

The power load device 4 is a variety of devices, such as lighting devices and air conditioning devices, and can receive power supply from at least one of the fuel cell device 10 and the power system 1 installed in the facility 20.

The fuel cell device 10 includes a fuel cell section 12 connected to the power grid 1, a power conversion section 11 that converts the power generated by the fuel cell section 12 to a predetermined voltage, frequency, and phase and supplies it to the power line 2, a fuel cell control section 13 that controls the operation of the fuel cell section 12 and the power conversion section 11, and a storage section 14 that stores information handled by the fuel cell device 10. The fuel cell device 10 may also include a fuel reformer that generates hydrogen, which is the fuel gas for the fuel cell section 12.
The fuel cell control unit 13 of the present embodiment corresponds to the "control unit" of the present invention.

The fuel cell control unit 13 can adjust the output power from the fuel cell device 10 to the power line 2 between a predetermined upper limit output power and a predetermined lower limit output power. For example, the fuel cell control unit 13 can maintain the output power of the fuel cell device 10 at the upper limit output power and operate it continuously. The fuel cell control unit 13 can also operate the fuel cell device 10 so that the output power of the fuel cell device 10 follows the load power of the power load device 4. For example, the fuel cell control unit 13 can operate the fuel cell device 10 so that the output power of the fuel cell device 10 follows the load power of the power load device 4 by adjusting the output power of the fuel cell device 10 so that the power measured by the power measurement unit 8 (i.e., the power supplied from the power system 1) becomes zero or close to zero.

The fuel cell control unit 13 has information about the output power supplied from the power conversion unit 11 to the power line 2 and information about the power measured by the power measurement unit 8, so it can derive the load power (= output power + measured power) of the power load device 4. When the sign of the measured power by the power measurement unit 8 is positive, it means that the load power is greater than the output power of the fuel cell device 10, and when the sign of the measured power by the power measurement unit 8 is negative, it means that the output power of the fuel cell device 10 is greater than the load power.

The fuel cell device 10 is connected to a remote control 7 that is operated by users of the facility 20 when issuing commands to the fuel cell device 10. Information about the output power and load power of the fuel cell device 10 is transmitted to the management device 30 via the remote control 7 and the router 6. For example, information about the output power and load power of the fuel cell device 10 is transmitted to the management device 30 at a predetermined timing, such as once every minute.

As described above, the management device 30 can transmit output control commands that determine the output power of the fuel cell devices 10 to multiple fuel cell devices 10. When the fuel cell devices 10 receive an output control command from the management device 30, they operate in a first operating mode that aims to supply output power determined based on the output control command during a controlled period that is the subject of the output control command, and operate in a second operating mode that is different from the first operating mode during a non-controlled period that is outside the controlled period.

The second operating mode is an operating mode that is preset in the multiple fuel cell devices 10. Alternatively, the management device 30 can transmit an operating mode control command that determines the second operating mode to the multiple fuel cell devices 10, and the fuel cell devices 10 determine the second operating mode according to the operating mode control command received from the management device 30.

Figure 3 is a diagram that illustrates a controlled period and a non-controlled period, and shows an example of a target output value during a controlled period. In the example shown in Figure 3, the control information (output control command) specifies the period from 12:00 to 15:00 as the controlled period. Therefore, this fuel cell device 10 operates in the first operating mode during the controlled period from 12:00 to 15:00, and operates in the second operating mode during the other non-controlled periods.

A specific example of the first operation mode will be described below.
As shown in FIG. 3, the fuel cell control unit 13 is configured to set, for each of a number of control timings included in a specified control period, a target output value of the output power to be supplied from the fuel cell unit 12 to the power line 2 to a value determined based on the predicted load power of the power load device 4 connected to the power line 2, and the target output value of the fuel cell unit 12 set at one control timing is configured not to be changed during the individual control period until the next control timing.

The predicted load power may be determined by the management device 30, and the value may be transmitted to the fuel cell control unit 13 of each facility 20. Alternatively, the fuel cell control unit 13 may determine the predicted load power based on the actual load power measured at the facility 20 as described above. In addition, for the determined predicted load power, a reference weather (e.g., sunny, etc.) and a reference temperature (e.g., 20°C, etc.) may be defined, and the fuel cell control unit 13 may revise the predicted load power based on the difference between the weather, temperature, etc. of the day and the reference weather, temperature, etc.

To be more specific, as shown in FIG. 3, a plurality of control timings are set in the control target period. The fuel cell control unit 13 derives the average value of the predicted load power of the power load device 4 during the individual control period. For example, when the fuel cell control unit 13 receives an output control command from the management device 30, which can be achieved by supplying power from the fuel cell unit 12 to the power line 2 that is a predetermined value greater than the average value of the predicted load power, the target output value is set to a power that is the predetermined value greater than the average value of the predicted load power. Note that, depending on the output control command, a target output value that is equal to or smaller than the average value of the predicted load power may be determined. The fuel cell control unit 13 does not change the target output value of the fuel cell unit 12 set at one control timing during the individual control period until the next control timing. As a result, frequent changes in the output power of the fuel cell unit 12 are avoided. As a result, deterioration of the fuel cell device 10 is suppressed.

In this embodiment, multiple fuel cell devices 10 having the above configuration are connected to the power system 1. The control timing is set for each of the multiple fuel cell devices 10. In other words, the control timing of each fuel cell device 10 installed in multiple facilities 20 may be the same or may be different.

In this embodiment, the length of the individual control period is constant. In addition, the length of the individual control period can be set based on, for example, the length of the control target period, the possible rate of change of the output of the fuel cell unit 12 (i.e., the time required to change the output of the fuel cell unit 12 from the lower limit output power to the upper limit output power), etc.

For example, when the length of an individual control period is set based on the length of the control target period, the length of the individual control period is set in the range of 1/100 to 1/2, preferably 1/30 to 1/5, of the length of the control target period. If the length of the control target period is 30 minutes, the length of the individual control period is in the range of 0.3 to 15 minutes, preferably 1 to 6 minutes.

In addition, if the length of the individual control period is set based on the time required to change the output of the fuel cell unit 12 from the lower limit output power to the upper limit output power, assuming that the time required to change the output of the fuel cell unit 12 from the lower limit output power of 50 W to the upper limit output power of 700 W is 6.5 minutes, the length of the individual control period is set in the range of 1/20 to 2.5 times the required time, preferably in the range of 1/5 to 1 time. In this case, the length of the individual control period is in the range of 0.325 minutes to 16.25 minutes, preferably in the range of 1.3 minutes to 6.5 minutes.

Figure 4 also shows an example of the target output value in the control period. In this example, when the actual load power of the power load device 4 in an individual control period deviates from the predicted load power in that individual control period, the fuel cell control unit 13 performs a correction to change the target output value of the fuel cell unit 12 in the next individual control period according to the deviation. For example, when a deviation occurs in which the actual load power of the power load device 4 in an individual control period becomes larger than the predicted load power in that individual control period, the fuel cell control unit 13 increases the target output value of the fuel cell unit 12 in the next individual control period by the increase in the deviation, and when a deviation occurs in which the actual load power of the power load device 4 in an individual control period becomes smaller than the predicted load power in that individual control period, the fuel cell control unit 13 decreases the target output value of the fuel cell unit 12 in the next individual control period by the decrease in the deviation.

In the example shown in FIG. 4, the fuel cell control unit 13 causes the fuel cell unit 12 to output power of a target output value determined based on the average value of the predicted load power of the power load device 4 during the individual control period T1. However, a deviation occurs in which the average value of the actual load power of the power load device 4 during this individual control period T1 is greater than the average value of the predicted load power during the individual control period T1. Therefore, the fuel cell control unit 13 increases the target output value of the fuel cell unit 12 during the next individual control period T2 from the uncorrected target output value to the corrected target output value by the increase in the deviation. As a result, the amount of power supplied from the fuel cell device 10 to the power system 1 during the control target period consisting of multiple individual control periods can be brought closer to the desired amount of power.

Second Embodiment
The second embodiment differs from the above embodiment in that the length of the individual target period is changed. A fuel cell device 10 and a fuel cell system according to the second embodiment will be described below, but a description of the same configuration as the above embodiment will be omitted.

In this embodiment, the fuel cell control unit 13 shortens the length of the individual control period as the deviation described above increases. For example, the memory unit 14 of the fuel cell device 10 stores the relationship between the magnitude of the deviation and the length of the individual control period or the amount of shortening of the individual control period. Therefore, the fuel cell control unit 13 can determine the length of the next individual control period depending on the magnitude of the deviation.

Figure 5 is an example of a target output value during a control period. As shown in the figure, during individual control period T3, the fuel cell control unit 13 operates to output power of a target output value determined based on the average value of the predicted load power of the power load device 4. However, there is a deviation in the average value of the actual load power of the power load device 4 during this individual control period T3 that is greater than the average value of the predicted load power during the individual control period T3. Therefore, the fuel cell control unit 13 sets the length of the next individual control period T4 to be shorter than the individual control period T3.

In this way, the increase or decrease correction of the target output value according to the deviation is performed at shorter time intervals as the deviation becomes larger. As a result, operation is prevented from continuing in a state where the target output value is not increased or decreased, that is, where no measures are taken to reduce the deviation. For example, in the example shown in FIG. 5 of this embodiment, the end timing of the second individual control period T4 within the control target period arrives earlier than the end timing of the second individual control period T2 shown in FIG. 4. This has the advantage that the increase correction of the target output value in the next individual control period is performed earlier.

<Another embodiment>
＜1＞
In the above embodiment, specific examples of the configurations of the fuel cell device and fuel cell system of the present invention have been given and explained, but the configurations can be modified as appropriate.

＜2＞
In the above embodiment, specific numerical values are given as examples for the output power, load power, length of the controlled period, length of the individual control period, etc., but these numerical values are given for illustrative purposes only and can be changed as appropriate.

＜3＞
In the above embodiment, the method of determining the predicted load power and the method of correcting the predicted load power in accordance with the weather, temperature, etc. have been described, but these methods can be changed as appropriate.

＜4＞
The configurations disclosed in the above embodiments (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, provided that no contradiction arises. Furthermore, the embodiments disclosed in this specification are illustrative, and the embodiments of the present invention are not limited thereto, and can be appropriately modified within the scope that does not deviate from the purpose of the present invention.

INDUSTRIAL APPLICABILITY The present invention can be used in a fuel cell device , a fuel cell system, and a power supply management system that can contribute to providing an appropriate adjustment power while suppressing deterioration of the device.

1 Power system 2 Power line 4 Power load device 10 Fuel cell device 12 Fuel cell unit 13 Fuel cell control unit (control unit)

Claims (6)

A fuel cell device comprising: a fuel cell unit connected to a power line connected to a power grid; and a control unit for controlling an operation of the fuel cell unit,
The control unit is
a target output value of the output power supplied from the fuel cell unit to the power line is set to a value determined based on a predicted load power of a power load device connected to the power line for each of a plurality of control timings included in a predetermined control target period, and the target output value of the fuel cell unit set at one of the control timings is configured not to be changed during an individual control period until the next of the control timings;
A fuel cell device that, when the actual load power of the power load device during the individual control period deviates from the predicted load power during the individual control period, changes the target output value of the fuel cell unit during the next individual control period according to the deviation. The control unit is
when a deviation occurs in which the actual load power of the power load device during the individual control period becomes larger than the predicted load power during the individual control period, increasing the target output value of the fuel cell unit during the next individual control period by an amount corresponding to the increase in the deviation,
2. A fuel cell device as described in claim 1, wherein when a deviation occurs in which the actual load power of the power load device during the individual control period is smaller than the predicted load power during the individual control period, the target output value of the fuel cell unit during the next individual control period is reduced by the amount of the deviation. The fuel cell device according to claim 1 or 2, wherein the control unit shortens the length of the individual control period as the deviation increases. A fuel cell system in which a plurality of fuel cell devices according to any one of claims 1 to 3 are connected to the power grid. The fuel cell system according to claim 4, wherein the control timing is set for each of the plurality of fuel cell devices. a fuel cell device according to any one of claims 1 to 3, which is installed in each of a plurality of facilities and capable of outputting electric power; and a management device capable of communicating with the plurality of fuel cell devices from outside the facilities;
the management device receives an electric power supply command for the control period determined by the electric power transaction from an aggregation coordinator that conducts electric power transactions in the electric power trading market, and transmits output control commands to the plurality of fuel cell devices that determine the output power of the fuel cell devices to be installed in each of the plurality of facilities, determined based on the supply command;
The fuel cell device is a power supply management system that determines the target output value based on the output control command received from the management device.

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