Power generation plan correction method, power generation plan correction device, and power generation system

Abstract

This power generation plan correction method includes: a step for receiving a power generation plan of a fuel cell device provided with a plurality of fuel cell power generation units; and a step for correcting the power generation plan of the fuel cell device so that the time change rate of the output of the fuel cell device changes according to the magnitude of a change in output of the fuel cell device when, in response to a change in output of the fuel cell device when shifting from a first unit period to a second unit period in the received power generation plan of the fuel cell device, the timing for changing the number of power generation units of the fuel cell power generation units is brought forward compared to the timing of shifting from the first unit period to the second unit period, and the first unit period is shifted to the second unit period in the received power generation plan of the fuel cell device.

Description

Power generation plan correction method, power generation plan correction device, and power generation system

[0001] The present disclosure relates to a power generation plan modification method, a power generation plan modification device, and a power generation system.

[0002] 2. Description of the Related Art Various proposals have been made in the past regarding output control of a power generation system.

[0003] As an example, Patent Document 1 discloses a fuel cell output control device that includes an operation plan storage means for storing the planned power generation amount of the fuel cell in each time period, and a power generation output switching means for controlling the switching of the fuel cell output power in each time period according to the planned power generation amount, wherein the power generation output switching means changes the output power of the fuel cell at a rate of change that allows the environmental temperature of the chemical reaction system in the fuel cell to maintain a quasi-thermal equilibrium state, and changes the output power so that the amount of power output by the fuel cell within the output power switching time interval is equal to the amount of power that would be output by the fuel cell within that time interval if the output power of the fuel cell were switched in steps in accordance with the planned power generation amount for that time interval.

[0004] Specifically, Patent Document 1 discloses that when the planned amount of power generation is to be switched from output power F1 to F2 at time t0, the power generation output switching means shifts the time at which the output power starts to be switched from F1 to F2 forward from time t0 by a time Δt = (F2 - F1) / (2s) relative to the time rate of change (s) of the amount of power generation that allows the environmental temperature of the chemical reaction system in the fuel cell to maintain a quasi-thermal equilibrium state, and changes the amount of power generation of the fuel cell at the time rate of change (s).

[0005] Japanese Patent Application Laid-Open No. 2005-19032

[0006] As an example, the present disclosure aims to provide a power generation plan correction method, a power generation plan correction device, and a power generation system that can more appropriately control the output of a fuel cell device equipped with multiple fuel cell power generation units than conventional methods based on corrections to the power generation plan of the fuel cell device.

[0007] In order to solve the above problem, a power generation plan correction method according to one aspect of the present disclosure comprises the steps of receiving a power generation plan for a fuel cell device having a plurality of fuel cell power generation units, and correcting the power generation plan of the fuel cell device so that the time rate of change of the output of the fuel cell device changes in accordance with the magnitude of the change in output of the fuel cell device when transitioning from the first unit period to the second unit period in the received power generation plan for the fuel cell device, by advancing the timing for changing the number of power generation units of the fuel cell power generation units to earlier than the timing for transitioning from the first unit period to the second unit period.

[0008] In addition, one embodiment of the power generation plan correction device of the present disclosure includes a communicator that receives a power generation plan of a fuel cell device having a plurality of fuel cell power generation units, and a controller that, in the received power generation plan of the fuel cell device, advances the timing for changing the number of power generation units of the fuel cell power generation units in response to a change in output of the fuel cell device when transitioning from a first unit period to a second unit period, compared to the timing for transitioning from the first unit period to the second unit period, and corrects the power generation plan of the fuel cell device so that the time rate of change of the output of the fuel cell device changes in accordance with the magnitude of the change in output of the fuel cell device when transitioning from the first unit period to the second unit period in the received power generation plan of the fuel cell device.

[0009] A power generation system according to one aspect of the present disclosure includes a fuel cell device including a plurality of fuel cell power generation units, and the power generation plan adjustment device described above.

[0010] The power generation plan correction method, power generation plan correction device, and power generation system according to one aspect of the present disclosure have the advantage of being able to control the output of a fuel cell device having multiple fuel cell power generation units more appropriately than conventional methods based on corrections to the power generation plan of the fuel cell device.

[0011] FIG. 1 is a diagram for explaining an example of the operation of a power generation plan correction device (power generation plan correction method) according to the present disclosure. FIG. 2 is a diagram for explaining an example of the operation of a power generation plan correction device (power generation plan correction method) according to the present disclosure. FIG. 3 is a diagram for explaining an example of the operation of a power generation plan correction device (power generation plan correction method) according to the present disclosure. FIG. 4 is a diagram illustrating an example of a power generation system according to a first embodiment. FIG. 5 is a flowchart illustrating an example of the operation of a power generation plan correction device in the power generation system according to the first embodiment. FIG. 6 is a flowchart illustrating an example of the operation of a power generation plan correction device in the power generation system according to a first example of the first embodiment. FIG. 7 is a flowchart illustrating an example of the operation of a power generation plan correction device in the power generation system according to a second example of the first embodiment. FIG. 8 is a flowchart illustrating an example of the operation of a power generation plan correction device in the power generation system according to a third example of the first embodiment. FIG. 9 is a flowchart illustrating an example of the operation of a power generation plan correction device in the power generation system according to a fourth example of the first embodiment. Fig. 10 is a flowchart showing an example of the operation of the power generation plan correction device (power generation plan correction method) in the power generation system of Example 5 of Embodiment 1. Fig. 11 is a diagram showing an example of the power generation system of Example 2.

[0012] Patent Document 1 discloses output control of a single fuel cell power generation unit, but does not consider output control of a fuel cell device having a plurality of fuel cell power generation units.

[0013] However, the output change of a fuel cell device having multiple fuel cell power generation units may behave differently from the output change of a single fuel cell power generation unit, and therefore it is often difficult to appropriately control the output of the former based on the output control of the latter.

[0014] Therefore, a first aspect of the power generation plan correction method of the present disclosure comprises the steps of receiving a power generation plan of a fuel cell device having a plurality of fuel cell power generation units, and correcting the power generation plan of the fuel cell device so that the time rate of change of the output of the fuel cell device changes in accordance with the magnitude of the change in output of the fuel cell device when transitioning from the first unit period to the second unit period in the received power generation plan of the fuel cell device, by bringing forward the timing of changing the number of power generation units of the fuel cell power generation units compared to the timing of transitioning from the first unit period to the second unit period.

[0015] According to the above, the power generation plan correction method of this aspect can control the output of a fuel cell apparatus including a plurality of fuel cell power generation units more appropriately than ever before based on correction of the power generation plan of the fuel cell apparatus.

[0016] First, as shown by the thick dotted line in the upper part of Figure 1, if the actual output change of the fuel cell device is delayed compared to the output change in the power generation plan when changing from the first unit period TA to the second unit period TB in the power generation plan, as shown by the thin solid line in Figure 1, a planning error corresponding to the power generation amount of area M in Figure 1 will occur between the power generation amount of the power generation plan in the second unit period TB and the power generation amount due to the actual output of the fuel cell device in the second unit period TB.

[0017] Therefore, in the power generation plan correction method of this embodiment, control is performed to advance the timing of changing the number of fuel cell power generation units relative to the timing of transition from the first unit period TA to the second unit period TB in response to a change in the output of the fuel cell device when transitioning from the first unit period TA to the second unit period TB in the received power generation plan of the fuel cell device, as shown by the thick dotted line in the lower part of Figure 1. As a result, the planning error of the power generation plan for the first unit period TA and the second unit period TB is allocated to the amount of power generation corresponding to the area M1 in Figure 1 and the amount of power generation corresponding to M2 in Figure 1, and as a result, the planning error of the power generation plan is mitigated.

[0018] Here, the present inventors have studied the difference between the behavior of output changes in a fuel cell device having a plurality of fuel cell power generation units and the behavior of output changes in a single fuel cell power generation unit.

[0019] First, in this disclosure, the "time rate of change of output" of a fuel cell device and a single fuel cell power generation unit is defined as the ratio of the magnitude of the change in output (power) of these devices divided by the time it takes for the actual output of these devices to reach the value after the change from the value before the change.

[0020] For example, as shown in the upper part of Figure 1, when the power generation plan of the fuel cell device transitions from a first unit period TA to a second unit period TB, if the output of the power generation plan changes from an output WA (low output) to an output WB (high output) as shown by the thick dotted line in Figure 1, the actual output of the fuel cell device will lag behind the output of the power generation plan of the fuel cell device by a time ΔT, as shown by the thin solid line in Figure 1, from the output WA to the output WB. Therefore, in this case, the "time rate of change of the output of the fuel cell device" is equivalent to (WB-WA) / ΔT.

[0021] Furthermore, for example, when the power generation plan of the fuel cell device transitions from a first unit period TA to a second unit period TB, if the output of the power generation plan changes from an output WA (low output) to an output WG (medium output) as shown by the dashed-dotted line in the upper part of Figure 1, the actual output of the fuel cell device will lag behind the output of the power generation plan of the fuel cell device by a time ΔT, as shown by the thin dashed-dotted line in Figure 1, from the output WA to the output WG. Therefore, in this case, the "time rate of change of the output of the fuel cell device" is equivalent to (WG-WA) / ΔT.

[0022] In other words, in the power generation plan correction method of this aspect, the "time rate of change of the output of the fuel cell device" changes depending on the magnitude of the change in the output of the fuel cell device when transitioning from the first unit period TA to the second unit period TB in the received power generation plan of the fuel cell device. This is for the following reason.

[0023] In a single fuel cell power generation unit (hereinafter referred to as a fuel cell power generation unit), the larger the change in output of the fuel cell power generation unit when changing from the previous unit period to the next unit period, the longer it takes for the actual output of the fuel cell power generation unit to reach the value after the change from the value before the change. Therefore, the "time rate of change of the output of the fuel cell power generation unit" is constant and does not depend on the magnitude of the change in the output of the fuel cell power generation unit.

[0024] In contrast, the power generation plan correction method of this embodiment changes the number of fuel cell power generation units while keeping the output of each fuel cell power generation unit constant (e.g., rated output) in response to changes in the output of the fuel cell device when transitioning from the first unit period TA to the second unit period TB in the received power generation plan of the fuel cell device. As a result, the time ΔT required for the actual output of the fuel cell device to change from a value before the change to a value after the change is constant and does not depend on the magnitude of the change in the output of the fuel cell device, so the "time rate of change of the output of the fuel cell device" changes depending on the magnitude of the change in the output of the fuel cell device.

[0025] Therefore, the power generation plan correction method of this embodiment appropriately corrects the power generation plan of the fuel cell device so that the change in the time rate of change of the output of the fuel cell device changes at the timing when the output of the fuel cell device changes when transitioning from the first unit period to the second unit period.

[0026] A second aspect of the power generation plan correction method of the present disclosure may include, in the first aspect of the power generation plan correction method, a step of bringing forward the timing of changing the number of power generating units of the fuel cell power generation units relative to the timing of transition from the second unit period to the third unit period in response to the change in output of the fuel cell device when transitioning from the second unit period to the third unit period in the received power generation plan of the fuel cell device, and correcting the power generation plan of the fuel cell device so that the time rate of change of the output of the fuel cell device changes in accordance with the magnitude of the change in output of the fuel cell device when transitioning from the second unit period to the third unit period in the received power generation plan of the fuel cell device.

[0027] According to the above, the power generation plan correction method of this embodiment appropriately corrects the power generation plan of the fuel cell device so that the time change rate of the output of the fuel cell device changes at the timing when the output of the fuel cell device changes when transitioning from the second unit period to the third unit period.

[0028] For example, in the case where the output of the fuel cell device increases both at the timing of change from the first unit period to the second unit period and at the timing of change from the second unit period to the third unit period, the power generation plan correction method of this embodiment can further mitigate the planning error of the power generation amount in the second unit period by bringing the timing of changing the number of fuel cell power generation units earlier than the timing of transition from the second unit period to the third unit period in response to the change in output of the fuel cell device when transitioning from the second unit period to the third unit period in the power generation plan of the fuel cell device.

[0029] 2, the amount of power generated by the actual output of the fuel cell device at the start of the second unit period TB is less than the amount of power generated in the power generation plan if the power generation schedule had not been brought forward by an amount equivalent to the area M2. In contrast, the amount of power generated by the actual output of the fuel cell device at the end of the second unit period TB is greater than the amount of power generated in the power generation plan if the power generation schedule had not been brought forward by an amount equivalent to the area M3. This further reduces the planning error in the amount of power generated in the second unit period.

[0030] A third aspect of the power generation plan correction method of the present disclosure may be the first aspect of the power generation plan correction method, in which the power generation plan of the fuel cell device is corrected so that the greater the magnitude of change in the output of the fuel cell device when transitioning from a first unit period to a second unit period in the received power generation plan of the fuel cell device, the greater the time rate of change in the output of the fuel cell device.

[0031] As described above, the time ΔT required for the actual output of the fuel cell device to reach the value after the change from the value before the change is constant and does not depend on the magnitude of the change in the output of the fuel cell device, so the "time rate of change of the output of the fuel cell device" changes depending on the magnitude of the change in the output of the fuel cell device.

[0032] Therefore, in this embodiment of the power generation plan correction method, the power generation plan of the fuel cell device is appropriately corrected so that the larger the change in the output of the fuel cell device when transitioning from the first unit period to the second unit period, the larger the time change rate of the output of the fuel cell device.

[0033] A fourth aspect of the power generation plan correction method of the present disclosure may be the second or third aspect of the power generation plan correction method, in which the power generation plan of the fuel cell device is corrected so that the greater the magnitude of change in the output of the fuel cell device when transitioning from the second unit period to the third unit period in the received power generation plan of the fuel cell device, the greater the time rate of change in the output of the fuel cell device.

[0034] As described above, the time ΔT required for the actual output of the fuel cell device to reach the value after the change from the value before the change is constant and does not depend on the magnitude of the change in the output of the fuel cell device, so the "time rate of change of the output of the fuel cell device" changes depending on the magnitude of the change in the output of the fuel cell device.

[0035] In this embodiment of the power generation plan correction method, the power generation plan of the fuel cell device is appropriately corrected so that the greater the magnitude of the change in the output of the fuel cell device when transitioning from the second unit period to the third unit period, the greater the time rate of change in the output of the fuel cell device.

[0036] A fifth aspect of the power generation plan correction method of the present disclosure may, in the second aspect of the power generation plan correction method, determine the length of time by which the timing for changing the number of fuel cell power generation units is advanced relative to the timing for transitioning from the first unit period to the second unit period so that the difference between the output amount for the second unit period in the received power generation plan of the fuel cell device and the output amount for the second unit period in the corrected power generation plan of the fuel cell device falls within a predetermined range.

[0037] Here, in the present disclosure, "output amount for the second unit period in the power generation plan of the fuel cell device" means the power generation amount (kWh) obtained by integrating the output (kW) of the fuel cell device in the power generation plan of the fuel cell device over the second unit period.

[0038] It may be desirable to set the range of the power generation amount guaranteed in the second unit period as a difference from the target value of the power generation amount in the second unit period.

[0039] Therefore, the present method for correcting a power generation plan determines the length of the time to be advanced so that the difference in the output amount for the second unit period before and after the correction of the power generation plan falls within a predetermined range, thereby reducing the possibility that the power generation amount for the second unit period will deviate from the range of power generation amount guaranteed for the second unit period compared to when such output control of the fuel cell device is not performed.

[0040] A sixth aspect of the power generation plan correction method of the present disclosure may, in the second aspect of the power generation plan correction method, determine the length of time by which to advance the timing for changing the number of fuel cell power generation units relative to the timing for transitioning from the first unit period to the second unit period so that the ratio of the difference between the output amount for the second unit period in the received power generation plan of the fuel cell device and the output amount for the second unit period in the corrected power generation plan of the fuel cell device to the output amount for the second unit period in the received power generation plan of the fuel cell device falls within a predetermined range.

[0041] It may be desirable to set the range of the power generation amount guaranteed in the second unit period as a ratio to the target value of the power generation amount in the second unit period.

[0042] Therefore, the present method for correcting a power generation plan determines the length of the time to be advanced so that the ratio of the difference in output amount for the second unit period before and after the correction of the power generation plan to the output amount before the correction falls within a predetermined range, thereby reducing the possibility that the power generation amount for the second unit period will deviate from the range of power generation amount guaranteed for the second unit period compared to when such output control of the fuel cell device is not performed.

[0043] The seventh aspect of the power generation plan correction method of the present disclosure is a power generation plan correction method according to any one of the first to sixth aspects, wherein the length of time that is brought forward may be less than half the length of the period during which the output of the fuel cell device changes when transitioning from the first unit period to the second unit period in the corrected power generation plan of the fuel cell device (hereinafter referred to as "the length of the period during which the output of the fuel cell device changes").

[0044] As described above, the power generation plan modification method of this aspect can reduce the possibility that the power generation amount in the first unit period will deviate from the range of the power generation amount guaranteed in the first unit period, compared to when the length of the time period for which the power generation plan is brought forward is equal to or greater than half the length of the period during which the output of the fuel cell device changes. The reason for this is as follows, as explained using the example shown in Figure 3.

[0045] In this power generation plan correction method, in response to an increase in the output of the fuel cell device when transitioning from the first unit period TA to the second unit period TB in the received power generation plan of the fuel cell device, the number of fuel cell power generation units is increased while maintaining the output of each fuel cell power generation unit constant. As a result, the time ΔT required for the actual output of the fuel cell device to reach the output WB (high output) after the change from the output WA before the change (low output) is constant and does not depend on the magnitude of the change in the output of the fuel cell device.

[0046] If the length of the time ΔTA to be advanced is half of the time ΔT as shown in Fig. 3, the planning error of the power generation plan for the first unit period TA and the second unit period TB is equally distributed (M1 = M2) between the power generation amount corresponding to the area M1 in Fig. 3 and the power generation amount corresponding to M2 in Fig. 3. In other words, the power generation amount in the first unit period TA is greater than the target value for the first unit period TA (WA x TA) by the amount corresponding to the area M1. Conversely, the power generation amount in the second unit period TB is less than the target value for the second unit period TB (WB x TB) by the amount corresponding to the area M2.

[0047] Here, if the ranges of power generation amounts guaranteed in the first unit period TA and the second unit period TB are set as a fixed percentage (%) of the target values ​​of the power generation amounts in the first unit period TA and the second unit period TB, respectively, the allowable range of the target value (WA×TA) for the first unit period TA is narrower than the allowable range of the target value (WB×TB) for the second unit period TB, because when the first unit period TA and the second unit period TB have the same length of time, the target value (WA×TA) for the former is smaller than the target value (WB×TB) for the latter.

[0048] For the above reasons, if the length of the time ΔTA that is advanced is more than half of the above-mentioned time ΔT, the amount of power generated in the first unit period TA is likely to deviate from the range of power generation amount guaranteed in the first unit period TA. However, the power generation plan correction method of this embodiment can appropriately alleviate such inconvenience because the length of the time that is advanced is less than half the length of the period during which the output of the fuel cell device changes.

[0049] An eighth aspect of the power generation plan correction device of the present disclosure comprises a communicator that receives a power generation plan of a fuel cell device having a plurality of fuel cell power generation units, and a controller that, in the received power generation plan of the fuel cell device, advances the timing for changing the number of power generation units of the fuel cell power generation units relative to the timing for transitioning from the first unit period to the second unit period in response to a change in output of the fuel cell device when transitioning from the first unit period to the second unit period, and corrects the power generation plan of the fuel cell device so that the time rate of change of the output of the fuel cell device changes in accordance with the magnitude of the change in output of the fuel cell device when transitioning from the first unit period to the second unit period in the received power generation plan of the fuel cell device.

[0050] As described above, the power generation plan correction device of this aspect can more appropriately control the output of a fuel cell device having a plurality of fuel cell power generation units based on the correction of the power generation plan of the fuel cell device than conventionally. Note that the details of the effects achieved by the power generation plan correction device of this aspect are similar to the effects achieved by the power generation plan correction method of the first aspect, and therefore will not be described here.

[0051] A power generation system according to a ninth aspect of the present disclosure includes a fuel cell device including a plurality of fuel cell power generation units, and the power generation plan adjustment device according to the eighth aspect.

[0052] As described above, the power generation system of this aspect can more appropriately control the output of a fuel cell device equipped with a plurality of fuel cell power generation units based on the modification of the power generation plan of the fuel cell device than conventionally. Note that the detailed effects of the power generation system of this aspect are similar to those of the power generation plan modification method of the first aspect, and therefore will not be described here.

[0053] <Further Aspects of the Present Disclosure> From the above description, the following aspects of the present disclosure can be further conceived.

[0054] A tenth aspect of the present disclosure provides a power generation plan correction method comprising the steps of receiving a power generation plan for a fuel cell device having a plurality of fuel cell power generation units, and correcting the power generation plan of the fuel cell device so as to bring forward the timing for changing the number of fuel cell power generation units relative to the timing for transitioning from the first unit period to the second unit period in response to a change in output of the fuel cell device when transitioning from the first unit period to the second unit period in the received power generation plan of the fuel cell device, wherein the length of the time that is brought forward is less than half the length of the period during which the output of the fuel cell device changes when transitioning from the first unit period to the second unit period in the corrected power generation plan of the fuel cell device.

[0055] The effects of the power generation plan modification method of this embodiment can be easily understood from the above description, and therefore will not be described further.

[0056] An eleventh aspect of the present disclosure's power generation plan correction method comprises the steps of receiving a power generation plan of a fuel cell device having a plurality of fuel cell power generation units, and if the received power generation plan of the fuel cell device shows an increase in output of the fuel cell device when transitioning from a first unit period to a second unit period, correcting the power generation plan of the fuel cell device so that the timing for increasing the number of fuel cell power generation units is brought forward compared to the timing for transitioning from the first unit period to the second unit period in response to the increase in output; and if the received power generation plan of the fuel cell device shows a decrease in output of the fuel cell device when transitioning from the first unit period to the second unit period, the timing for reducing the number of fuel cell power generation units is not brought forward compared to the timing for transitioning from the first unit period to the second unit period in response to the decrease in output.

[0057] In this power generation planning method, the increase in output of the fuel cell device when transitioning from the previous unit period to the next unit period in the power generation plan of the fuel cell device is addressed by increasing the number of fuel cell power generation units generating electricity while maintaining the output of each fuel cell power generation unit constant.

[0058] In this case, in order to mitigate the occurrence of planning errors due to a delay in the actual increase in output of the fuel cell device relative to the output increase in the power generation plan of the fuel cell device, the timing for increasing the number of fuel cell power generation units is brought forward.

[0059] On the other hand, in the power generation plan of the fuel cell device, a drop in the output of the fuel cell device when transitioning from the previous unit period to the next unit period is also addressed by reducing the number of generating fuel cell power generation units while maintaining the output of each generating fuel cell power generation unit constant.

[0060] In this case, because the operation of only the desired number of fuel cell power generation units is stopped, the fuel cell device's ability to follow output changes is higher than that when the fuel cell device's output increases. Therefore, as shown in Figure 3, the time it takes for the actual output of the fuel cell device to reach the output WC (low output) from the output WA before the change is shorter than the time ΔT, so the timing to reduce the number of fuel cell power generation units does not need to be advanced from the timing of transition from the second unit period TB to the third unit period TC. Note that Figure 3 shows the output of the fuel cell device decreasing when transitioning from the second unit period TB to the third unit period TC, but this is an example, and the output decrease when transitioning from the first unit period TA to the second unit period TB also does not need to be advanced.

[0061] Specific examples of the above-described aspects of the present disclosure will be described below with reference to the accompanying drawings. Each of the specific examples described below is an example of the above-described aspects of the present disclosure. Therefore, unless otherwise stated in the claims, the shapes, numerical values, components, arrangement positions and connection forms of the components shown below do not limit the scope of the claims.

[0062] Furthermore, among the components described below, components that are not described in the independent claims that represent the highest concept of the present disclosure are described as optional components. Furthermore, in the drawings, components with the same reference numerals may not be described in detail. The drawings are schematic illustrations of each component for ease of understanding, and the shapes, dimensional ratios, and the like may not be accurately depicted.

[0063] Furthermore, in the operation of the apparatus, the order of steps may be changed or known steps may be added as necessary.

[0064] First Embodiment [Device Configuration] FIG. 4 is a diagram showing an example of a power generation system according to a first embodiment.

[0065] As shown in FIG. 4, the power generation system 10 of this embodiment includes a fuel cell device 15 having a plurality of fuel cell power generation units, and a power generation plan adjustment device 20.

[0066] Here, the power generation system 10 may be, for example, a system that supplies a large amount of power to a power grid. For example, the power generation system 10 may include a group of power generation units each consisting of a plurality of fuel cell power generation units including a fuel cell stack. In this case, the fuel cell device 15 corresponds to each group obtained by dividing the group of power generation units. The detailed configuration of such a power generation system 10 will be described in a second embodiment.

[0067] In this embodiment, the output of the fuel cell device 15 is controlled by varying the number of fuel cell power generation units. This allows the output of the fuel cell power generation units to be kept constant at the rated output during power generation, which is advantageous in terms of power generation efficiency and lifespan of the fuel cell power generation units compared to when the output of the fuel cell power generation units is controlled.

[0068] In the example shown in FIG. 4 , the power generation plan adjustment device 20 includes a communication device 21 and a controller 23 .

[0069] The communicator 21 is a receiver that receives a power generation plan for the fuel cell device 15, which includes a plurality of fuel cell power generation units. For example, the communicator 21 may receive the power generation plan for each unit period transmitted from a terminal or a server via a communication network.

[0070] The "unit period" may be, for example, about 30 minutes, but is not limited to this. The "unit period" can be set to an appropriate period based on the configuration of the power generation system 10, etc.

[0071] It should be noted that users of the terminal or server include direct or indirect users of the power generation plan modification device 20. A direct user of the power generation plan modification device 20 is, for example, an administrator of the power generation plan modification device 20. An indirect user of the power generation plan modification device 20 can be, for example, the owner of the power generation system 10. Such an owner may be a consumer who receives the service of supplying power generated by the power generation system 10, or may be a power generation company that supplies power to consumers using the power generation system 10.

[0072] The controller 23 advances the timing for changing the number of fuel cell power generation units in response to the change in output of the fuel cell device 15 when transitioning from the first unit period TA to the second unit period TB in the received power generation plan of the fuel cell device 15, compared to the timing for transitioning from the first unit period TA to the second unit period TB, and corrects the power generation plan of the fuel cell device 15 so that the time rate of change of the output of the fuel cell device 15 changes in accordance with the magnitude of the change in output of the fuel cell device 15 when transitioning from the first unit period TA to the second unit period TB in the received power generation plan of the fuel cell device 15.

[0073] The "magnitude of the change in the output of the fuel cell device 15" may be either the magnitude of the absolute value of the change in the output, or the magnitude of the ratio of the change in the output.

[0074] The controller 23 may be any device having a control function, and may include an arithmetic processing unit (not shown) and a memory unit (not shown) that stores a control program. The arithmetic processing unit reads and executes the control program stored in the memory unit, thereby performing predetermined control in the controller 23. An example of the arithmetic processing unit is a microprocessor. An example of the memory unit is a memory. The controller 23 may directly control the operation, including the output, of the fuel cell power generation unit in the fuel cell device 15. Furthermore, if the fuel cell power generation unit is provided with a control device (not shown) that controls its own operation, including the output, the controller 23 may indirectly control the operation, including the output, of the fuel cell power generation unit in the fuel cell device 15 via this control device.

[0075] [Operation] Fig. 5 is a flowchart showing an example of the operation of the power generation plan correction device (power generation plan correction method) in the power generation system of the first embodiment. The following operation may be performed, for example, by the arithmetic processing unit of the controller 23 reading out a control program from the storage unit of the controller 23. However, it is not necessarily required that the following operation be performed by the controller 23. An operator may perform some of the operation. In the following example, a case where the operation is controlled by the controller 23 will be described.

[0076] First, when the operation of the power generation plan modification device 20 starts, in step S1, the power generation plan of the fuel cell device 15 having a plurality of fuel cell power generation units is received via the communicator 21. For example, the power generation plan transmitted from a terminal or a server via a communication network may be received for each unit period.

[0077] Next, in step S2, in response to the change in output of the fuel cell device 15 when transitioning from the first unit period TA to the second unit period TB in the power generation plan of S1, the timing for changing the number of power generating units of the fuel cell power generation unit is brought forward compared to the timing for transitioning from the first unit period TA to the second unit period TB, and control is performed to modify the power generation plan of the fuel cell device so that the time rate of change of the output of the fuel cell device 15 changes according to the magnitude of the change in output of the fuel cell device 15 when transitioning from the first unit period TA to the second unit period TB in the power generation plan of S1.

[0078] Here, in step S2, based on the rate of increase / decrease in the output of the fuel cell device 15 at the start of planning for the second unit period TB, the length of time (set value) by which the timing for changing the number of fuel cell power generation units is advanced relative to the timing for transitioning from the first unit period TA to the second unit period TB may be determined as shown in Table 1 below.

[0079] Specifically, if the rate of change in the output of the fuel cell device 15 at the start of the second unit period TB is 50% or less, the advance time is set to "0 minutes."

[0080] Furthermore, if the rate of change in the output of the fuel cell device 15 at the start of the second unit period TB is greater than 50% and equal to or less than 100%, the advance time is set to "2 minutes".

[0081] Furthermore, if the rate of change in the output of the fuel cell device 15 at the start of the second unit period TB is greater than 100%, the advance time is set to "4 minutes".

[0082] The rate of increase or decrease in the output of the fuel cell device 15 at the start of the second unit period TB is calculated, for example, by the following formula (1).

[0083] Increase / decrease rate = (output immediately after the start of the plan - output immediately before the start of the plan) / output immediately before the start of the plan... (1) As an example, if the plan is for the output of the fuel cell device 15 to increase in steps from 50 kW to 200 kW at the start of the plan for the second unit period TB, the increase / decrease rate of the output of the fuel cell device 15 at the start of the plan for the second unit period TB is calculated to be (200 - 50) / 50 = 300%.

[0084] As an example, if the output of the fuel cell device 15 is planned to decrease in a stepwise manner from 200 kW to 120 kW at the end of the second unit period TB (the start of the next unit period), the rate of increase or decrease in the output of the fuel cell device 15 at the end of the second unit period TB (the start of the next unit period) is calculated to be (120-200) / 200=-40%.

[0085] Here, when the power generation plan of the fuel cell device 15 in step S1 is received over a "predetermined period," the control of step S2 may be executed for part or all of the timing of change from the "previous unit period" to the "next unit period" included in the "predetermined period." For example, when the "predetermined period" is three days and the "unit period" is 30 minutes, the control of step S2 may be executed for part or all of the timing of change from the "previous 30 minutes" to the "next 30 minutes" included in the three days. That is, using the example of Table 1 as an example, if the "predetermined period" includes a period in which the rate of increase or decrease of the output of the fuel cell device 15 at the start of the plan for the "unit period" is 50% or less and a period in which the rate of increase or decrease exceeds 50%, the control of step S2 is executed for part of the timing of change from the "previous unit period" to the "next unit period."

[0086] However, the values ​​of the output (kW) of the fuel cell device 15, the rate of increase / decrease (%), the advance time (minutes), the "predetermined period," and the "unit period" are merely examples and are not limited to these examples. These can be set to appropriate values ​​based on the configuration of the power generation system 10, etc.

[0087] When the above operation of the power generation plan adjustment device 20 is completed, power generation by the fuel cell device 15 is carried out at the appropriate time based on the power generation plan.

[0088] According to the present embodiment described above, the output of the fuel cell system 15 having a plurality of fuel cell power generation units can be controlled more appropriately than ever before based on the correction of the power generation plan of the fuel cell system 15 .

[0089] Specifically, according to this embodiment, as shown by the thick dotted line in the lower part of Figure 1, control is performed to advance the timing for changing the number of fuel cell power generation units relative to the timing for transitioning from the first unit period TA to the second unit period TB in response to a change in output of the fuel cell device 15 when transitioning from the first unit period TA to the second unit period TB in the received power generation plan for the fuel cell device 15. As a result, the planning error in the power generation plan for the first unit period TA and the second unit period TB is allocated to the amount of power generation corresponding to the area M1 in Figure 1 and the amount of power generation corresponding to M2 in Figure 1, and as a result, the planning error in the power generation plan is mitigated.

[0090] Furthermore, according to this embodiment, the number of fuel cell power generating units is changed while maintaining the output of each fuel cell power generating unit constant (for example, rated output) in response to changes in the output of the fuel cell device 15 when transitioning from the first unit period TA to the second unit period TB in the received power generation plan for the fuel cell device 15. As a result, the time ΔT required for the actual output of the fuel cell device 15 to change from a value before the change to a value after the change is constant and does not depend on the magnitude of the change in the output of the fuel cell device 15, so the "time rate of change of the output of the fuel cell device 15" changes depending on the magnitude of the change in the output of the fuel cell device.

[0091] Therefore, the power generation plan correction method, power generation plan correction device 20, and power generation system 10 of this embodiment appropriately correct the power generation plan of the fuel cell device 15 so that the time change rate of the output of the fuel cell device 15 changes at the timing when the output of the fuel cell device 15 changes when transitioning from the first unit period TA to the second unit period TB.

[0092] First Example A method for correcting a power generation plan according to a first example of the first embodiment is the same as that of the first embodiment, except for the control content by the controller 23, which will be described below.

[0093] FIG. 6 is a flowchart showing an example of the operation of the power generation plan correction device (power generation plan correction method) in the power generation system of the first example of the first embodiment.

[0094] The following operations may be performed, for example, by the arithmetic processing unit of the controller 23 reading out a control program from the storage unit of the controller 23. However, it is not essential that the following operations be performed by the controller 23. An operator may perform some of the operations. In the following example, a case where the operations are controlled by the controller 23 will be described.

[0095] Note that steps S1 and S2 in FIG. 6 are similar to steps S1 and S2 in FIG. 5, and therefore detailed description thereof will be omitted.

[0096] In step S3, in response to the change in output of the fuel cell device 15 when transitioning from the second unit period TB to the third unit period TC in the power generation plan of S1, the timing for changing the number of power generating units of the fuel cell power generation unit is brought forward compared to the timing for transitioning from the second unit period TB to the third unit period TC, and control is performed to modify the power generation plan of the fuel cell device 15 so that the time rate of change of the output of the fuel cell device 15 changes according to the magnitude of the change in output of the fuel cell device 15 when transitioning from the second unit period TB to the third unit period TC in the power generation plan of S1.

[0097] In step S3, the method for determining the length (set value) of the above-mentioned advance time at the start of the plan for the third unit period TC is the same as that described in step S2, and therefore detailed description thereof will be omitted.

[0098] Furthermore, the control in step S3 when the power generation plan for the fuel cell device 15 in step S1 is received for a "predetermined period" is the same as that described in step S2, and therefore a detailed description thereof will be omitted.

[0099] According to the present embodiment described above, the power generation plan of the fuel cell device 15 is appropriately corrected so that the time rate of change of the output of the fuel cell device 15 changes at the timing when the output of the fuel cell device 15 changes when transitioning from the second unit period TB to the third unit period TC.

[0100] For example, in the power generation plan correction method of this embodiment, if the output of the fuel cell device 15 increases both at the timing of change from the first unit period TA to the second unit period TB and at the timing of change from the second unit period TB to the third unit period TC, the timing of changing the number of fuel cell power generation units generating electricity can be brought forward compared to the timing of transition from the second unit period TB to the third unit period TC in the power generation plan of the fuel cell device 15, thereby further mitigating the planning error in the power generation amount in the second unit period TB.

[0101] 2, the amount of power generated by the actual output of the fuel cell device 15 at the start of the second unit period TB is less than the amount of power generated in the power generation plan if the power generation schedule had not been brought forward by an amount equivalent to the area M2. In contrast, the amount of power generated by the actual output of the fuel cell device at the end of the second unit period TB is greater than the amount of power generated in the power generation plan if the power generation schedule had not been brought forward by an amount equivalent to the area M3. This further reduces the planning error in the amount of power generated in the second unit period TB.

[0102] The power generation plan adjustment method, the power generation plan adjustment device 20, and the power generation system 10 of this embodiment may be the same as those of the first embodiment except for the above-mentioned features.

[0103] Second Example A method for correcting a power generation plan according to a second example of the first embodiment is similar to that of the first embodiment, except for the control performed by the controller 23, which will be described below.

[0104] FIG. 7 is a flowchart showing an example of the operation of the power generation plan adjustment device (power generation plan adjustment method) in the power generation system of the second example of the first embodiment.

[0105] The following operations may be performed, for example, by the arithmetic processing unit of the controller 23 reading out a control program from the storage unit of the controller 23. However, it is not essential that the following operations be performed by the controller 23. An operator may perform some of the operations. In the following example, a case where the operations are controlled by the controller 23 will be described.

[0106] Note that step S1 in FIG. 7 is similar to step S1 in FIG. 5, and therefore a detailed description thereof will be omitted.

[0107] In step S2A, in response to the change in output of the fuel cell device 15 when transitioning from the first unit period TA to the second unit period TB in the power generation plan of S1, the timing for changing the number of power generating units of the fuel cell power generation unit is brought forward compared to the timing for transitioning from the first unit period TA to the second unit period TB, and control is performed to modify the power generation plan of the fuel cell device 15 so that the greater the magnitude of the change in output of the fuel cell device 15 when transitioning from the first unit period TA to the second unit period TB in the power generation plan of S1, the greater the time change rate of the output of the fuel cell device 15.

[0108] As described above, the time ΔT required for the actual output of the fuel cell device 15 to reach the value after the change from the value before the change is constant and does not depend on the magnitude of the change in the output of the fuel cell device 15, so the "time rate of change of the output of the fuel cell device" changes depending on the magnitude of the change in the output of the fuel cell device 15.

[0109] Therefore, in the power generation plan correction method of this embodiment, the power generation plan of the fuel cell device 15 is appropriately corrected so that the larger the magnitude of the change in the output of the fuel cell device 15 when transitioning from the first unit period TA to the second unit period TB, the larger the time change rate of the output of the fuel cell device 15 becomes.

[0110] The power generation plan adjustment method, power generation plan adjustment device 20, and power generation system 10 of this embodiment may be the same as those of the first embodiment or the first example of the first embodiment, except for the above-mentioned features.

[0111] Third Example A method of correcting a power generation plan in a third example of the first embodiment is the same as that in the first example of the first embodiment, except for the control content by the controller 23, which will be described below.

[0112] FIG. 8 is a flowchart showing an example of the operation of the power generation plan adjustment device (power generation plan adjustment method) in the power generation system of the third example of the first embodiment.

[0113] The following operations may be performed, for example, by the arithmetic processing unit of the controller 23 reading out a control program from the storage unit of the controller 23. However, it is not essential that the following operations be performed by the controller 23. An operator may perform some of the operations. In the following example, a case where the operations are controlled by the controller 23 will be described.

[0114] Note that step S1 in Fig. 8 is similar to step S1 in Fig. 5, and therefore a detailed description thereof will be omitted. Also, step S2A in Fig. 8 is similar to step S2A in Fig. 7, and therefore a detailed description thereof will be omitted.

[0115] In step S3A, in response to the change in output of the fuel cell device 15 when transitioning from the second unit period TB to the third unit period TC in the power generation plan of S1, the timing for changing the number of power generating units of the fuel cell power generation unit is brought forward compared to the timing for transitioning from the second unit period TB to the third unit period TC, and control is performed to modify the power generation plan of the fuel cell device 15 so that the greater the magnitude of the change in output of the fuel cell device 15 when transitioning from the second unit period TB to the third unit period TC in the power generation plan of S1, the greater the time change rate of the output of the fuel cell device 15.

[0116] As described above, the time ΔT required for the actual output of the fuel cell device 15 to reach the value after the change from the value before the change is constant and does not depend on the magnitude of the change in the output of the fuel cell device 15, so the "time rate of change of the output of the fuel cell device" changes depending on the magnitude of the change in the output of the fuel cell device 15.

[0117] Therefore, in the power generation plan correction method of this embodiment, the power generation plan of the fuel cell device 15 is appropriately corrected so that the larger the magnitude of the change in the output of the fuel cell device 15 when transitioning from the second unit period TB to the third unit period TC, the larger the time change rate of the output of the fuel cell device 15.

[0118] Other than the above-mentioned features, the power generation plan adjustment method, power generation plan adjustment device 20, and power generation system 10 of this embodiment may be the same as those of the first embodiment and any one of the first and second examples of the first embodiment.

[0119] Fourth Example A method of correcting a power generation plan in a fourth example of the first embodiment is the same as that in the first example of the first embodiment, except for the control content by the controller 23, which will be described below.

[0120] FIG. 9 is a flowchart showing an example of the operation of the power generation plan adjustment device (power generation plan adjustment method) in the power generation system of the fourth example of the first embodiment.

[0121] The following operations may be performed, for example, by the arithmetic processing unit of the controller 23 reading out a control program from the storage unit of the controller 23. However, it is not essential that the following operations be performed by the controller 23. An operator may perform some of the operations. In the following example, a case where the operations are controlled by the controller 23 will be described.

[0122] Note that steps S1 to S3 in FIG. 9 are similar to steps S1 to S3 in FIG. 6, and therefore detailed description thereof will be omitted.

[0123] In step S4, the length of time by which the timing for changing the number of fuel cell power generation units is advanced from the timing of transition from the first unit period TA to the second unit period TB is determined so that the absolute value of the difference (MA-MB) between the output amount MA of the second unit period TB in the power generation plan of S1 and the output amount MB of the second unit period TB in the revised power generation plan of S1 falls within a predetermined range.

[0124] Here, in this disclosure, "output amount for the second unit period TB in the power generation plan of the fuel cell device" means the power generation amount (kWh) obtained by integrating the output (kW) of the fuel cell device 15 in the power generation plan of the fuel cell device 15 over the second unit period TB (the same applies below).

[0125] It may be desirable to set the range of power generation amount guaranteed in the second unit period TB as a difference from the target value of power generation amount in the second unit period TB. This is because when the output (kW) of the fuel cell device is less than a predetermined value, if the range of power generation amount guaranteed in the second unit period TB is defined as a ratio to the target value of power generation amount, the range of power generation amount guaranteed in the second unit period TB becomes too narrow.

[0126] For example, when the unit period of the power generation plan is 30 minutes and the output (kW) of the fuel cell device is less than 100 kW, the guaranteed range of power generation amount for every 30 minutes may be set to "target value (kWh) of power generation amount ±5 kWh." However, the numerical values ​​of the guaranteed range of the output (kW) and power generation amount (kWh) of the fuel cell device 15 are merely examples and are not limited to this example.

[0127] As described above, the power generation plan correction method of this embodiment determines the length of the time to be advanced so that the absolute value of the difference (MA-MB) in the output amount of the second unit period TB before and after the power generation plan correction falls within a predetermined range, thereby reducing the possibility that the power generation amount of the second unit period TB will deviate from the range of power generation amount guaranteed for the second unit period TB compared to when such output control of the fuel cell device 15 is not performed.

[0128] Other than the above-mentioned features, the power generation plan adjustment method, power generation plan adjustment device 20, and power generation system 10 of this embodiment may be the same as those of the first embodiment and any of the first to third examples of the first embodiment.

[0129] Fifth Example A method of correcting a power generation plan in a fifth example of the first embodiment is the same as that in the first example of the first embodiment, except for the control content by the controller 23, which will be described below.

[0130] FIG. 10 is a flowchart showing an example of the operation of the power generation plan adjustment device (power generation plan adjustment method) in the power generation system of the fifth example of the first embodiment.

[0131] The following operations may be performed, for example, by the arithmetic processing unit of the controller 23 reading out a control program from the storage unit of the controller 23. However, it is not essential that the following operations be performed by the controller 23. An operator may perform some of the operations. In the following example, a case where the operations are controlled by the controller 23 will be described.

[0132] Note that steps S1 to S3 in FIG. 10 are similar to steps S1 to S3 in FIG. 6, and therefore detailed description thereof will be omitted.

[0133] In step S4A, the length of time by which the timing for changing the number of fuel cell power generation units to be changed is advanced from the timing of transition from the first unit period TA to the second unit period TB is determined so that the ratio "(MA-MB) / MA" of the absolute value of the difference (MA-MB) between the output amount MA of the second unit period TB in the power generation plan of S1 and the output amount MB of the second unit period TB in the revised power generation plan of the fuel cell device 15 to the output amount MA of the second unit period TB in the power generation plan falls within a specified range.

[0134] It may be desirable to set the range of the power generation amount guaranteed in the second unit period as a ratio to the target value of the power generation amount in the second unit period TB.

[0135] For example, when the unit period of the power generation plan is 30 minutes and the output (kW) of the fuel cell device is 100 kW or more, the guaranteed range of the power generation amount for every 30 minutes may be set to "the target value (kWh) of the power generation amount ±5%." However, the numerical values ​​of the guaranteed range of the output (kW) and power generation amount (kWh) of the fuel cell device 15 are merely examples and are not limited to this example.

[0136] As described above, the power generation plan correction method of this embodiment determines the length of the time to be advanced so that the ratio "(MA-MB) / MA", which is the ratio of the absolute value of the difference in output amount (MA-MB) of the second unit period TB before and after the correction of the power generation plan to the output amount MA before the correction, falls within a predetermined range, thereby reducing the possibility that the power generation amount of the second unit period TB will deviate from the range of power generation amount guaranteed for the second unit period TB, compared to when such output control of the fuel cell device 15 is not performed.

[0137] Other than the above-mentioned features, the power generation plan adjustment method, power generation plan adjustment device 20, and power generation system 10 of this embodiment may be the same as those of the first embodiment and any of the first to third examples of the first embodiment.

[0138] (Example 6) The method of correcting the power generation plan in Example 6 of the first embodiment is the same as that in the first embodiment, except that the length of the time ΔTA to be brought forward is less than half the length of the time ΔT during which the output of the fuel cell device 15 changes when transitioning from the first unit period TA to the second unit period TB in the corrected power generation plan of the fuel cell device 15 (hereinafter referred to as "the length of the time ΔT during which the output of the fuel cell device 15 changes").

[0139] Specifically, referring to Table 1 (above), the length of the time ΔT during which the output of the fuel cell device 15 changes is approximately 10 minutes, whereas the length of the time ΔTA to be advanced is set to "0 minutes," less than half of the time ΔT, if the rate of change in the output of the fuel cell device 15 at the start of the second unit period TB is 50% or less. Furthermore, the length of the time ΔTA to be advanced is set to "2 minutes," less than half of the time ΔT, if the rate of change in the output of the fuel cell device 15 at the start of the second unit period TB is greater than 50% but less than 100%. Furthermore, the length of the time ΔTA to be advanced is set to "4 minutes," less than half of the time ΔT, if the rate of change in the output of the fuel cell device 15 at the start of the second unit period TB is greater than 100%.

[0140] However, the values ​​of the length of the time ΔT during which the output of the fuel cell device 15 changes, the rate of change (%), and the advance time (minutes) are merely examples and are not limited to these examples.

[0141] The power generation plan correction method of this embodiment increases the number of fuel cell power generation units while maintaining constant the output of each fuel cell power generation unit that is generating electricity in response to an increase in the output of the fuel cell device 15 when transitioning from the first unit period TA to the second unit period TB in the received power generation plan of the fuel cell device. As a result, the time ΔT required for the actual output of the fuel cell device 15 to reach the output WB (high output) after the change from the output WA before the change (low output) is constant and does not depend on the magnitude of the change in the output of the fuel cell device 15.

[0142] If the length of the time ΔTA to be advanced is half of the time ΔT as shown in Fig. 3, the planning error of the power generation plan for the first unit period TA and the second unit period TB is equally distributed (M1 = M2) between the power generation amount corresponding to the area M1 in Fig. 3 and the power generation amount corresponding to M2 in Fig. 3. In other words, the power generation amount in the first unit period TA is greater than the target value for the first unit period TA (WA x TA) by the amount corresponding to the area M1. Conversely, the power generation amount in the second unit period TB is less than the target value for the second unit period TB (WB x TB) by the amount corresponding to the area M2.

[0143] Here, if the ranges of power generation amounts guaranteed in the first unit period TA and the second unit period TB are set as a fixed percentage (%) of the target values ​​of the power generation amounts in the first unit period TA and the second unit period TB, respectively, the allowable range of the target value (WA×TA) for the first unit period TA is narrower than the allowable range of the target value (WB×TB) for the second unit period TB, because when the first unit period TA and the second unit period TB have the same length of time, the target value (WA×TA) for the former is smaller than the target value (WB×TB) for the latter.

[0144] For the above reasons, if the length of the time ΔTA to be advanced is more than half of the above-mentioned time ΔT, the power generation amount for the first unit period TA is likely to deviate from the range of power generation amount guaranteed for the first unit period TA. However, the power generation plan correction method of this embodiment can appropriately alleviate such inconvenience because the length of the time ΔTA to be advanced is less than half the length of the time ΔT during which the output of the fuel cell device 15 changes.

[0145] In the power generation plan for the fuel cell system 15, the output of the fuel cell system 15 is reduced when transitioning from the previous unit period to the next unit period by reducing the number of fuel cell power generation units while maintaining the output of each fuel cell power generation unit constant. In this case, the operation of a desired number of fuel cell power generation units is simply stopped, so the ability of the fuel cell system 15 to follow output changes is higher than when the output of the fuel cell system 15 increases. Therefore, as shown in Figure 3, the time it takes for the actual output of the fuel cell system 15 to change from the pre-change output WA (high output) to the post-change output WC (low output) is shorter than the time ΔT, so the timing for changing the number of fuel cell power generation units does not need to be brought forward compared to the timing of transition from the second unit period TB to the third unit period TC.

[0146] Other than the above-mentioned features, the power generation plan adjustment method, power generation plan adjustment device 20, and power generation system 10 of this embodiment may be the same as those of the first embodiment and any of the first to fifth examples of the first embodiment.

[0147] Second Embodiment FIG. 11 is a diagram showing an example of a power generation system according to a second embodiment.

[0148] As shown in FIG. 11, the power generation system 10 of this embodiment includes a fuel cell device 15, a power generation plan adjustment device 20, and control devices 30A to 30E.

[0149] Here, the internal configuration of the power generation plan adjustment device 20 is the same as that of the first embodiment, and therefore a detailed description thereof will be omitted.

[0150] In the example shown in FIG. 11, the power generation system 10 includes a group of power generation units made up of a plurality of fuel cell power generation units each including a fuel cell stack.

[0151] This power generation unit group is made up of multiple fuel cell power generation units. Although not shown, each of these fuel cell power generation units is made up of a fuel cell stack, a power conditioner that converts DC power generated by the fuel cell stack into AC power and outputs it to the power grid, and a control device that controls the operation of these devices.

[0152] In this example, the power generation unit groups are divided into fuel cell power generation units a1-an belonging to group A, fuel cell power generation units b1-bn belonging to group B, fuel cell power generation units c1-cn belonging to group C, fuel cell power generation units d1-dn belonging to group D, and fuel cell power generation units e1-en belonging to group E. All of the fuel cell power generation units belonging to one group are also simply referred to as "fuel cell power generation units within the group." The fuel cell devices of the present disclosure are, for example, each of groups A to E.

[0153] However, the above configuration of the power generation unit group is merely an example and is not limited to this example. For example, the power generation unit group may be formed by grouping a plurality of fuel cell power generation units within a single group.

[0154] Control devices 30A to 30E are provided for fuel cell power generation units a1 to an in group A, fuel cell power generation units b1 to bn in group B, fuel cell power generation units c1 to cn in group C, fuel cell power generation units d1 to dn in group D, and fuel cell power generation units e1 to en in group E, respectively, and control the operation of each fuel cell power generation unit within the group.

[0155] For example, the control device 30A controls the output of each of the fuel cell power generation units a1 to an belonging to group A via a communication network to enable efficient operation (e.g., optimization of life span) of the fuel cell power generation units a1 to an.

[0156] The control devices 30A to 30E may be any device that has a control function, and include a processing unit (not shown), a storage unit (not shown) that stores a control program, and a communication device (not shown). The processing unit reads and executes the control program stored in the storage unit, thereby performing predetermined control in the control devices 30A to 30E. An example of the processing unit is a microprocessor. An example of the storage unit is a memory.

[0157] The power generation plan modification device 20 sends various information related to the modified power generation plan, etc., to each of the control devices 30A-30E via a communications network in response to, for example, an external user's output request. Each control device 30A-30E adjusts the number of fuel cell power generation units that will generate power among the multiple fuel cell power generation units belonging to each of the fuel cell devices 15A-15E, depending on the power generation output in the received power generation plan. In other words, a change in the output of the fuel cell device 15 corresponds to a change in the number of fuel cell power generation units belonging to the fuel cell device 15 that are generating power. In other words, a change in the output of the fuel cell device 15 is achieved by changing the number of fuel cell power generation units that generate power.

[0158] The effects achieved by the power generation system 10 of this embodiment are similar to those described in any one of the first embodiment and the first to sixth examples of the first embodiment, and therefore a description thereof will be omitted.

[0159] The above configuration of the power generation system 10 is merely an example and is not limited to this example. For example, the power generation plan modification device 20 may be equipped with the control functions of the control devices 30A to 30E and directly control the operation of each of the fuel cell power generation units in the group.

[0160] The first embodiment, the first to sixth examples of the first embodiment, and the second embodiment may be combined with one another as long as they do not exclude one another. From the above description, many improvements and other embodiments of the present disclosure will be apparent to those skilled in the art. Therefore, the above description should be construed as merely illustrative and is provided for the purpose of teaching those skilled in the art the best mode for carrying out the present disclosure. Details of the structure and / or function thereof may be substantially changed without departing from the spirit of the present disclosure.

[0161] One aspect of the present disclosure can be used in a power generation plan correction method, a power generation plan correction device, and a power generation system that can control the output of a fuel cell device having multiple fuel cell power generation units more appropriately than conventional methods based on corrections to the power generation plan of the fuel cell device.

[0162] 10: Power generation system 15: Fuel cell device 15A: Fuel cell device 15B: Fuel cell device 15C: Fuel cell device 15D: Fuel cell device 15E: Fuel cell device 20: Power generation plan correction device 21: Communication device 23: Controller 30A: Control device 30B: Control device 30C: Control device 30D: Control device 30E: Control device A: Group B: Group C: Group D: Group E: Group TA: First unit period TB: Second unit period TC: Third unit period WA: Output WB: Output WC: Output WG: Output a1 to an: Fuel cell power generation unit b1 to bn: Fuel cell power generation unit c1 to cn: Fuel cell power generation unit d1 to dn: Fuel cell power generation unit e1 to en: Fuel cell power generation unit

Claims

1. A method for correcting a power generation plan, comprising: receiving a power generation plan for a fuel cell device having a plurality of fuel cell power generation units; and correcting the power generation plan of the fuel cell device so that the time rate of change of the output of the fuel cell device changes in accordance with the magnitude of the change in output of the fuel cell device when transitioning from the first unit period to the second unit period in the received power generation plan of the fuel cell device, by bringing forward the timing for changing the number of power generation units of the fuel cell power generation units relative to the timing for transitioning from the first unit period to the second unit period.

2. A power generation plan correction method as described in claim 1, comprising a step of bringing forward the timing of changing the number of power generating units of the fuel cell power generation units in response to a change in output of the fuel cell device when transitioning from the second unit period to the third unit period in the received power generation plan of the fuel cell device, compared to the timing of transition from the second unit period to the third unit period, and correcting the power generation plan of the fuel cell device so that the time rate of change of the output of the fuel cell device changes in accordance with the magnitude of the change in output of the fuel cell device when transitioning from the second unit period to the third unit period in the received power generation plan of the fuel cell device.

3. A power generation plan correction method as described in claim 1, which corrects the power generation plan of the fuel cell device so that the larger the magnitude of change in the output of the fuel cell device when transitioning from the first unit period to the second unit period in the received power generation plan of the fuel cell device, the larger the time rate of change in the output of the fuel cell device.

4. A power generation plan correction method as described in claim 2 or 3, which corrects the power generation plan of the fuel cell device so that the larger the magnitude of change in the output of the fuel cell device when transitioning from the second unit period to the third unit period in the received power generation plan of the fuel cell device, the larger the time change rate of the output of the fuel cell device.

5. A power generation plan correction method as described in claim 2, which determines the length of time by which the timing for changing the number of power generating units of the fuel cell power generation unit is advanced from the timing of transition from the first unit period to the second unit period so that the difference between the output amount for the second unit period in the received power generation plan of the fuel cell device and the output amount for the second unit period in the corrected power generation plan of the fuel cell device falls within a predetermined range.

6. A power generation plan correction method as described in claim 2, which determines the length of time by which the timing for changing the number of power generating units of the fuel cell power generation unit is advanced from the timing of transition from the first unit period to the second unit period so that the ratio of the difference between the output amount for the second unit period in the received power generation plan of the fuel cell device and the output amount for the second unit period in the corrected power generation plan of the fuel cell device to the output amount for the second unit period in the received power generation plan of the fuel cell device falls within a predetermined range.

7. A power generation plan modification method according to any one of claims 1 to 6, wherein the length of the time period to be brought forward is less than half the length of the period during which the output of the fuel cell device changes when transitioning from the first unit period to the second unit period in the modified power generation plan of the fuel cell device.

8. A power generation plan correction device comprising: a communicator that receives a power generation plan of a fuel cell device having a plurality of fuel cell power generation units; and a controller that, in the received power generation plan of the fuel cell device, advances the timing for changing the number of power generation units of the fuel cell power generation units in response to a change in output of the fuel cell device when transitioning from a first unit period to a second unit period, compared to the timing for transitioning from the first unit period to the second unit period, and corrects the power generation plan of the fuel cell device so that the time rate of change of the output of the fuel cell device changes in accordance with the magnitude of the change in output of the fuel cell device when transitioning from the first unit period to the second unit period in the received power generation plan of the fuel cell device.

9. A power generation system comprising: a fuel cell device having a plurality of fuel cell power generation units; and the power generation plan correction device according to claim 8.

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