JP2010257751A - Method of controlling fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To keep a target output by simple control even when voltage drop is caused. <P>SOLUTION: The method of controlling a fuel cell system includes a first step of setting a target output level for a fuel cell module; a second step of supplying fuel gas corresponding to fuel gas data; a third step of producing a current corresponding to the current data; a fourth step of detecting a present output level of the fuel cell module; a fifth step of comparing the present output level with the target output level; a sixth step of adjusting a fuel gas flow rate supplied to the fuel cell module; a seventh step of adjusting current obtaining from the fuel cell module; an eighth step of updating the fuel gas data corresponding to the target output level; and a ninth step of updating the current data corresponding to the target output level. At least any one of the sixth step, seventh step, eighth step or ninth step is carried out based on the comparing result of the fifth step. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention provides a fuel cell module having a fuel cell stack in which a plurality of fuel cells that generate power by an electrochemical reaction between a fuel gas and an oxidant gas are stacked, and a control device that controls a power generation amount of the fuel cell module. The present invention relates to a battery system control method.

  In general, a solid oxide fuel cell (SOFC) uses an oxide ion conductor, for example, stabilized zirconia, as a solid electrolyte, and an electrolyte / electrode in which an anode electrode and a cathode electrode are disposed on both sides of the solid electrolyte. A joined body (hereinafter also referred to as MEA) is sandwiched between separators (bipolar plates). This fuel cell is normally used as a fuel cell stack in which a predetermined number of electrolyte / electrode assemblies and separators are laminated.

  In this type of fuel cell stack, the output may decrease due to the degradation of power generation performance. Therefore, in order to suppress deterioration of battery characteristics, for example, a fuel cell power generator disclosed in Patent Document 1 is known.

  This fuel cell power generator measures the load current and voltage of the fuel cell, records the measured load current and voltage as a change with time corresponding to the operation time, and changes the change with time and the healthy battery output of the fuel cell. The state of the fuel cell is evaluated by comparing the change with time, and the flow rate of at least one of the fuel and the oxidant is controlled according to the evaluation result. That is, by measuring the load current and voltage of the fuel cell, the deterioration state and the operation state of the fuel cell are detected, and the amount of the reaction gas of the fuel or oxidant supplied to the fuel cell is adjusted to an amount suitable for the fuel cell situation This is intended to stabilize the characteristics of the fuel cell.

  Further, a fuel cell system disclosed in Patent Document 2 includes a polymer electrolyte fuel cell, a fuel supply unit, an oxidant supply unit, a polymer electrolyte fuel cell, a fuel supply unit, and an oxidant supply unit. And a control means for controlling.

  The fuel cell system includes an open circuit voltage measuring unit that measures an open circuit voltage of the polymer electrolyte fuel cell, and the control unit controls at least one of the fuel supply unit and the oxidant supply unit according to the open circuit voltage. I have control. Specifically, a first operation mode in which a preset first supply amount of fuel and oxidant is supplied to the polymer electrolyte fuel cell, and a supply amount of at least one of fuel or oxidant are reduced. And a second operation mode in which the second supply amount of fuel and oxidant are supplied to the polymer electrolyte fuel cell.

JP-A-8-96825 JP 2007-234347 A

  However, in Patent Document 1 described above, time measurement is required because the load current and voltage of the fuel cell are measured as changes over time. Moreover, since the deterioration state of the fuel cell is detected by measuring the voltage, the fuel utilization rate may change greatly.

  Furthermore, since changes with time before and after the fuel cell is stopped are recorded, it is possible to determine the deterioration of the fuel cell only when the fuel cell is stopped. Therefore, in the case of a fuel cell with few start-stops, there is a problem that the number of times of judging deterioration is reduced and deterioration cannot be judged at an appropriate time. In addition, Patent Document 1 aims to operate at an optimum reaction gas utilization rate, and cannot provide the output desired by the user or the operation with high efficiency.

  Further, in Patent Document 2 described above, at least one of the fuel supply means or the oxidant supply means is controlled according to the open circuit voltage, and deterioration can be detected if the load is not in a no-load state (open circuit state). There is a problem that you can not.

  Moreover, since at least one of the fuel supply means and the oxidant supply means is controlled according to the open circuit voltage, the optimum fuel supply means or oxidant supply means in a closed circuit state that is actually used cannot be controlled. There is a problem.

  In addition, there is a difference between the open circuit state, which is a state for detecting deterioration, and the closed circuit state, which is a state for actually operating in accordance with the deterioration, and the actual operation according to the deterioration is not performed accurately. There is a fear.

  The present invention solves this type of problem, and an object of the present invention is to provide a control method of a fuel cell system capable of maintaining a target output with simple control even when a voltage drop is caused. And

  The present invention provides a fuel cell module having a fuel cell stack in which a plurality of fuel cells that generate power by an electrochemical reaction between a fuel gas and an oxidant gas are stacked, and a control device that controls a power generation amount of the fuel cell module. The present invention relates to a battery system control method.

  In this control method, fuel gas data and current data corresponding to the target output value of the fuel cell module are preset, and the first step of setting the target output value of the fuel cell module; A second step of supplying a fuel gas corresponding to the fuel gas data based on a setting result of the step; a third step of obtaining a current corresponding to the current data based on the setting result of the first step; A fourth step of detecting a current output value of the fuel cell module; a fifth step of comparing the target output value or a specified range of the target output value with the current output value; and A sixth step of adjusting the flow rate of the supplied fuel gas; a seventh step of adjusting a current obtained from the fuel cell module; and an eighth step of updating the fuel gas data corresponding to the target output value. And extent, and a ninth step of updating the current data corresponding to the target output value. Based on the comparison result of the fifth step, at least one of the sixth step, the seventh step, the eighth step, or the ninth step is performed.

  Further, in this control method, when it is determined in the fifth step that the current output value is less than the target output value or less than the specified range of the target output value, the control method supplies the fuel cell module in the sixth step. After increasing the fuel gas flow rate and then increasing the current obtained from the fuel cell module in the seventh step, it is preferable to return to the fourth step.

  For this reason, when the fuel cell cannot obtain the desired target output value, the fuel gas supplied to the fuel cell is increased, and then the current taken out from the fuel cell is increased, thereby increasing the rapid fuel consumption. Changes in the utilization rate, in particular, fuel depletion due to an excessive increase in the fuel utilization rate are suppressed. Therefore, the deterioration of the fuel cell, specifically, the electrolyte / electrode assembly is suppressed, and the reliability and durability of the fuel cell module are improved.

  Further, in this control method, when it is determined in the fifth step that the current output value exceeds the target output value or exceeds the specified range of the target output value, the current obtained from the fuel cell module in the seventh step It is preferable to reduce the flow rate of the fuel gas supplied to the fuel cell module in the sixth step and then return to the fourth step.

  Thus, when the current output value of the fuel cell exceeds the target output value, first, the current taken out from the fuel cell is reduced, and then the flow rate of the fuel gas supplied to the fuel cell is reduced. In addition, drastic change in fuel utilization rate, in particular, fuel depletion due to excessive increase in fuel utilization rate is suppressed. For this reason, the deterioration of the electrolyte / electrode assembly is suppressed, and the reliability and durability of the fuel cell module are improved.

  Furthermore, in this control method, it is preferable that the sixth step and the seventh step are performed in a state where the fuel utilization rate is maintained within a preset specified range. Accordingly, in the sixth step of adjusting the flow rate of the fuel gas supplied to the fuel cell module and the seventh step of adjusting the current obtained from the fuel cell module, the fuel utilization rate is within a preset specified range. Since the operation is performed in a maintained state, a sudden change in the fuel utilization rate, in particular, fuel depletion due to an excessive increase in the fuel utilization rate is suppressed. Thereby, deterioration of the electrolyte / electrode assembly is suppressed, and the reliability and durability of the fuel cell module are improved.

  In the control method, in the fifth step, when it is determined that the current output value is equal to the target output value or within the specified range of the target output value, at least the sixth step or the seventh step. It is preferable to determine whether or not the adjustment is performed in any of the above. When the fuel gas flow rate and the current value are not adjusted, it is not necessary to update the fuel gas data corresponding to the target output value and the current data corresponding to the target output value. For this reason, output reduction is not caused in the fuel cell module, and the fuel cell module can be efficiently generated.

  Furthermore, when it is determined that the adjustment has been performed at least in either the sixth step or the seventh step, it is preferable to perform at least one of the eighth step and the ninth step. After the target output value is obtained, the fuel gas data and the current data corresponding to the target output value are updated. Therefore, if the same target output value is to be obtained from the next time, the target output is quickly and reliably obtained. It becomes possible to supply the fuel gas and take out the current according to the value.

  Furthermore, in this control method, the fuel cell module is preferably a solid oxide fuel cell module. Therefore, the fuel cell is a high-temperature fuel cell that generates a large amount of heat, and the durability and life of the fuel cell system can be further improved. Moreover, by applying it to the solid oxide fuel cell module, it is possible to suppress a temperature drop when changing the output, and a high temperature operation can be maintained.

  According to the present invention, based on the comparison result between the target output value and the current output value, at least the step of adjusting the flow rate of the fuel gas supplied to the fuel cell module, the step of adjusting the current obtained from the fuel cell module, the target Either the step of updating the fuel gas data corresponding to the output value or the step of updating the current data corresponding to the target output value is performed.

  For this reason, even when the fuel cell cannot obtain a desired target output value due to a voltage drop, the target output value can be reliably obtained by adjusting the fuel gas flow rate or the current.

  Next, at least one of the fuel gas data corresponding to the target output value and the current data corresponding to the target output value is updated. Therefore, when the same target output value is obtained after the next time, it becomes possible to quickly and accurately supply the fuel gas and take out the current in accordance with the target output value.

It is a schematic structure explanatory view showing a mechanical system circuit of a fuel cell system to which a control method according to an embodiment of the present invention is applied. It is a circuit diagram of the fuel cell system. It is a flowchart explaining the said control method. It is explanatory drawing of the electric power generation performance of a fuel cell module. It is explanatory drawing of the electric current value and fuel gas flow volume corresponding to the target output value of the said fuel cell module. It is explanatory drawing of the range of the said target output value. It is explanatory drawing at the time of increasing an output from the fall state of the said power generation performance. It is explanatory drawing of rewriting of the said electric current value and the said fuel gas flow volume corresponding to the said target output value.

  As shown in FIG.1 and FIG.2, the fuel cell system 10 which concerns on embodiment of this invention is used for various uses, such as a vehicle-mounted use other than stationary use.

  The fuel cell system 10 includes a fuel cell module (SOFC module) 12 that generates electric power by an electrochemical reaction between a fuel gas (hydrogen gas) and an oxidant gas (air), and a raw fuel (for example, city gas) in the fuel cell module 12. ) 16, an oxidant gas supply device (including an air pump) 18 for supplying the oxidant gas to the fuel cell module 12, and the fuel cell module 12. A water supply device (including a water pump) 20 that supplies water, a power conversion device 22 that converts DC power generated in the fuel cell module 12 into required specification power, and a power generation amount of the fuel cell module 12 are controlled. And a control device 24.

  The fuel cell module 12 includes a solid oxide fuel cell stack 28 in which a plurality of solid oxide fuel cells 26 are stacked in the vertical direction. The fuel cell 26 includes, for example, an electrolyte / electrode assembly (MEA) in which a cathode electrode and an anode electrode are provided on both surfaces of an electrolyte composed of an oxide ion conductor such as stabilized zirconia. The electrolyte / electrode assembly is formed in a disc shape and constitutes a sealless type fuel cell.

  As shown in FIG. 2, a fuel gas supply communication hole 30 is provided at the center of the fuel cell stack 28 so as to extend in the stacking direction (the direction of arrow A), and each fuel cell is extended from the fuel gas supply communication hole 30. Fuel gas is supplied to the 26 anode electrodes.

  A plurality of oxidant gas supply communication holes 32 are provided concentrically around the fuel gas supply communication hole 30 at the center edge of the fuel cell stack 28, and each fuel cell 26 is connected through the oxidant gas supply communication hole 32. Air is supplied to the cathode electrode. The oxidant gas supply communication hole 32 also serves as the exhaust gas communication hole 34 for discharging the fuel gas used in the anode electrode and the air used in the cathode electrode.

  As shown in FIGS. 1 and 2, on the upper end side (or lower end side in the stacking direction) of the fuel cell stack 28, there is a heat exchanger 36 that heats the oxidant gas before supplying it to the fuel cell stack 28. In order to generate a mixed fuel of raw fuel and water vapor, an evaporator 38 that evaporates water and a reformer 40 that reforms the mixed fuel to generate a reformed gas are disposed.

  On the lower end side (or upper end side in the stacking direction) of the fuel cell stack 28, a load for applying a tightening load along the stacking direction (arrow A direction) to the fuel cells 26 constituting the fuel cell stack 28. An application mechanism 42 is disposed (see FIG. 2).

The reformer 40 removes higher hydrocarbons (C ₂₊ ) such as ethane (C ₂ H ₆ ), propane (C ₃ H ₈ ) and butane (C ₄ H ₁₀ ) contained in city gas (raw fuel). , A pre-reformer for steam reforming to a fuel gas mainly containing methane (CH ₄ ), hydrogen, and CO, and is set to an operating temperature of several hundred degrees Celsius.

  The fuel cell 26 has an operating temperature as high as several hundred degrees Celsius. In the electrolyte / electrode assembly, methane in the fuel gas is reformed to obtain hydrogen and CO, and this hydrogen and CO are supplied to the anode electrode. The

  The heat exchanger 36 includes an exhaust gas passage 44 for flowing used reaction gas (hereinafter also referred to as exhaust gas) discharged from the fuel cell stack 28, and air for flowing air, which is a fluid to be heated, in a counterflow with the exhaust gas. And a passage 46. The upstream side of the air passage 46 communicates with the air supply pipe 48, and the downstream side of the air passage 46 communicates with the oxidant gas supply communication hole 32 of the fuel cell stack 28.

  The evaporator 38 is provided with a raw fuel passage 50 and a water passage 52. The raw fuel passage 50 is connected to the raw fuel supply device 16, and the reformer 40 communicates with the fuel gas supply communication hole 30. The water passage 52 is connected to the water supply device 20, while the oxidant gas supply device 18 is connected to the air supply pipe 48.

  The raw fuel supply device 16, the oxidant gas supply device 18, and the water supply device 20 are controlled by a control device 24, and the control device 24 includes a voltage for monitoring the voltage and current during power generation of the fuel cell stack 28. The current monitor 56 is electrically connected. For example, a commercial power source 58 (or a load, a secondary battery, or the like) is connected to the power conversion device 22 (see FIG. 2).

  As shown in FIGS. 1 and 2, the fuel cell system 10 includes a first flow rate sensor 62a that detects the flow rate of raw fuel (fuel gas) supplied from the raw fuel supply device 16 to the evaporator 38, and oxidant gas supply. A second flow rate sensor 62b that detects the flow rate of air (oxidant gas) supplied from the device 18 to the heat exchanger 36, and a third flow rate that detects the flow rate of water supplied from the water supply device 20 to the evaporator 38. A flow sensor 62c is provided.

  The first to third flow rate sensors 62 a, 62 b and 62 c are connected to the control device 24. The control device 24 has a function of controlling the supply amount of fuel gas from the raw fuel supply device 16, the supply amount of air from the oxidant gas supply device 18, and the supply amount of water from the water supply device 20. It has a function of adjusting the current of the battery stack 28.

  The operation of the fuel cell system 10 configured as described above will be described below.

As shown in FIGS. 1 and 2, under the driving action of the raw fuel supply device 16, for example, city gas (CH ₄ , C ₂ H ₆ , C ₃ H ₈ , C ₄ H ₁₀₎ is provided in the raw fuel passage 50. And other raw fuel is supplied. On the other hand, under the driving action of the water supply device 20, water is supplied to the water passage 52, and oxidant gas is supplied to the air supply pipe 48 via the oxidant gas supply device 18. Is supplied.

In the evaporator 38, steam is mixed with the raw fuel to obtain a mixed fuel, and this mixed fuel is supplied to the reformer 40. The mixed fuel is steam reformed in the reformer 40 to remove (reform) C ₂₊ hydrocarbons to obtain a fuel gas (reformed gas) mainly composed of methane. This fuel gas is supplied to the fuel gas supply passage 30 of the fuel cell stack 28.

  On the other hand, when the air supplied from the air supply pipe 48 to the heat exchanger 36 moves along the air passage 46 of the heat exchanger 36, the air is heated between the exhaust gas that moves along the exhaust gas passage 44, which will be described later. Exchange is performed and preheated to the desired temperature. The air heated by the heat exchanger 36 is supplied to the oxidant gas supply communication hole 32 of the fuel cell stack 28.

  Therefore, fuel gas is supplied to the anode electrode of each fuel cell 26 and air is supplied to the cathode electrode, and power generation is performed by a chemical reaction. The exhaust gas containing the fuel gas and air used for the reaction is discharged from the fuel cell stack 28 through the exhaust gas passage 44 as an off gas.

  Next, the control method according to the present embodiment will be described along the flowchart shown in FIG.

  First, the power generation performance (relationship between output and power generation efficiency) of the fuel cell module 12 is set by the ratio of the fuel gas flow rate as shown in FIG. For example, while the target output value is set, the control device 24 stores a map of the current value and the fuel gas flow rate with respect to the target output value, as shown in FIG.

  Therefore, the control method according to the present embodiment will be described below.

  In this control method, fuel gas data and current data corresponding to the target output value of the fuel cell module 12 are preset, and the first step of setting the target output value of the fuel cell module 12; A second step of supplying fuel gas corresponding to the fuel gas data based on the setting result of the first step; and a third step of obtaining a current corresponding to the current data based on the setting result of the first step. A fourth step of detecting a current output value of the fuel cell module 12, a fifth step of comparing the target output value or a specified range of the target output value with the current output value, and the fuel A sixth step of adjusting a flow rate of the fuel gas supplied to the battery module 12, a seventh step of adjusting a current obtained from the fuel cell module 12, and the fuel gas device corresponding to the target output value. It has a eighth step of updating the data, and a ninth step of updating the current data corresponding to the target output value.

  Based on the comparison result of the fifth step, at least one of the sixth step, the seventh step, the eighth step, or the ninth step is performed.

  Specifically, as shown in the flowchart of FIG. 3, in the fuel cell system 10, the target output value (voltage × current) of the fuel cell module 12 is set by the control device 24 (step S1).

  As shown in FIG. 5, the control device 24 sets the fuel gas flow rate (Qf8) corresponding to the target output value (required output value) (Pr8) from the map stored in advance (step S2), and the target A current value (I8) corresponding to the output value is set (step S3). Therefore, in the fuel cell module 12, the fuel gas adjusted to the fuel gas flow rate set in step S2 is supplied, and the current set in step S3 is taken out. Note that step S2 and step S3 may be performed in the reverse order.

  Next, it progresses to step S4 and the control apparatus 24 detects the present output value (voltage x electric current) (FC output value) of the fuel cell module 12. FIG. The detected current output value of the fuel cell module 12 is compared with a specified range (or target output value) of the target output value (step S5).

  At this time, when the target output value of the fuel cell module 12 is 1000 W, for example, the coefficient α is set as shown in FIG. Here, α = 0.05 is a case where priority is given to responsiveness, and α = 0.01 is a case where priority is given to accuracy. In other cases, the maximum value (MAX) of the current output value is set as the target output value. This is to prevent excessive output (including reverse power flow).

  If it is determined in step S5 that the current output value is less than the specified range of the target output value or exceeds the specified range of the target output value (NO in step S5), the process proceeds to step S6, where the current output value is It is determined whether it is less than the target output value.

  If it is determined that the current output value of the fuel cell module 12 is less than the target output value (YES in step S6), the process proceeds to step S7, and the flow rate of the fuel gas is increased. Further, after the flow rate of the fuel gas is increased, the process proceeds to step S8, and the current taken out from the fuel cell module 12 is increased.

  Specifically, as shown in FIG. 7, at the initial operation point P1, the required output value is satisfied, and the output and efficiency decrease due to deterioration or the like, and reach the deterioration operation point P2. For this reason, while the fuel utilization rate Uf is maintained constant, the flow rate of the fuel gas supplied to the fuel cell module 12 is increased, and the current value obtained from the fuel cell module 12 is increased. Therefore, it is adjusted to the deterioration suppression operation point P3, and a desired required output value (target output value) is obtained.

  If adjustment of said step S7 and step S8 is performed, it will progress to step S9. Since the fuel gas flow rate and the current are adjusted, the adjustment execution flag is turned on, and then the process returns to step S4.

  On the other hand, if it is determined in step S6 that the current output value exceeds the target output value (NO in step S6), the process proceeds to step S10, and first, the current obtained from the fuel cell module 12 is decreased. Next, after the flow rate of the fuel gas supplied to the fuel cell module 12 is reduced (step S11), the process proceeds to step S9.

  If it is determined in step S5 that the current output value is within the specified range of the target output value (YES in step S5), the process proceeds to step S12 to determine whether or not the adjustment execution flag is on. Is done. If it is determined that the adjustment execution flag is ON (YES in step S12), that is, if it is determined that the adjustment process of step S7 and step S8 or the adjustment process of step S10 and step S11 has been performed, the process proceeds to step S13. The fuel gas data corresponding to the target output value is updated.

  In step S14, the current data corresponding to the target output value is updated. Specifically, as shown in FIG. 8, the fuel gas flow rate is rewritten from Qf8 to Qf8 + Qfα with respect to the required output value Pr8, while the current value is rewritten from I8 to I8 + Iα. When the rewriting process is completed, the process proceeds to step S15, and the adjustment execution flag is turned off.

  In this case, in this embodiment, based on the comparison result between the target output value and the current output value, at least the step of adjusting the flow rate of the fuel gas supplied to the fuel cell module 12 and the current obtained from the fuel cell module 12 are adjusted. A process of updating fuel gas data corresponding to the target output value, or a process of updating current data corresponding to the target output value.

  Thereby, even when the fuel cell 26 cannot obtain a desired target output value due to a voltage drop, the target output value can be reliably obtained by adjusting the fuel gas flow rate or adjusting the current. .

  Next, at least one of the fuel gas data corresponding to the target output value and the current data corresponding to the target output value is updated. For this reason, when the same target output value is obtained after the next time, it is possible to quickly and accurately supply the fuel gas corresponding to the target output value and extract the current.

  When it is determined that the current output value is less than the target output value (YES in step S6), the flow rate of the fuel gas supplied to the fuel cell module 12 is increased (step S7), and then the fuel cell After increasing the current obtained from the module 12 (step S8), the process returns from step S9 to step S4.

  Accordingly, if the fuel cell 26 cannot supply a desired output value due to a voltage drop even if the fuel gas corresponding to the target output value is supplied and the current is drawn, the flow rate of the supplied fuel gas is first increased. Then, the current to be taken out is increased. As a result, a rapid change in the fuel utilization rate, in particular, fuel depletion due to an excessive increase in the fuel utilization rate is suppressed, and deterioration of the electrolyte / electrode assembly is suppressed. Therefore, the reliability and durability of the fuel cell module 12 are improved. There is an advantage of improvement.

  Further, when it is determined that the current output value exceeds the target output value (NO in step S6), first, the current obtained from the fuel cell module 12 is reduced (step S10), and then the fuel cell module. After the flow rate of the fuel gas supplied to 12 is reduced (step S11), the process returns from step S9 to step S4.

  For this reason, even if the fuel gas flow rate corresponding to the target output value is supplied and the current value is extracted, if the current output value> the target output value of the fuel cell 26, the current to be extracted is reduced, The fuel gas supplied is reduced. Therefore, a rapid change in the fuel utilization rate, particularly fuel depletion due to an excessive increase in the fuel utilization rate is suppressed, deterioration of the electrolyte / electrode assembly is suppressed, and the reliability and durability of the fuel cell module 12 are improved. .

  Furthermore, the step of adjusting the flow rate of the fuel gas supplied to the fuel cell module 12 and the step of adjusting the current obtained from the fuel cell module 12 maintain that the fuel utilization rate is within a preset specified range. It is done in the state. Specifically, the range of the fuel utilization rate (Uf) in the general fuel cell system 10 is in the range of 10% to 80%.

  In the present embodiment, in the sixth step and the seventh step, when emphasizing responsiveness, the specified range of the fuel utilization rate is set to ± 5%, while when emphasizing durability, the fuel is used. The specified range of usage rate is set to ± 1%. As a result, in the fuel gas flow rate adjustment step and the current adjustment step, a sudden change in the fuel usage rate, in particular, fuel depletion due to an excessive increase in the fuel usage rate is suppressed. For this reason, deterioration of the electrolyte / electrode assembly is suppressed, and the reliability and durability of the fuel cell module 12 are improved.

  Further, when it is determined that the current output value is equal to the target output value (YES in step S5), it is determined whether or not adjustment has been performed at least in either the sixth step or the seventh step. (Step S12). That is, when the fuel gas flow rate adjustment and the current adjustment are not performed, neither adjustment is necessary, and the fuel gas data corresponding to the target output value and the current data corresponding to the target output value are updated. There is nothing. Therefore, the output of the fuel cell module 12 is not reduced, and the fuel cell module 12 can efficiently generate power.

  Further, when it is determined that the adjustment has been performed at least in either the sixth step or the seventh step, at least the eighth step (update of fuel gas data) or the ninth step (update of current data). ) One of them has been done. Thereby, when it is desired to obtain the same target output value from the next time, it becomes possible to quickly and accurately supply the fuel gas and take out the current according to the target output value.

  Furthermore, the fuel cell module 12 is a solid oxide fuel cell module. For this reason, the fuel cell 26 is a high-temperature fuel cell that generates a large amount of heat, and can further improve the durability and life of the fuel cell system 10. In addition, when applied to the solid oxide fuel cell module, it is possible to suppress a temperature drop when the output is changed, and it is possible to maintain a high temperature operation.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell system 12 ... Fuel cell module 16 ... Raw fuel supply device 18 ... Oxidant gas supply device 20 ... Water supply device 22 ... Power converter 24 ... Control device 26 ... Fuel cell 28 ... Fuel cell stack 36 ... Heat exchange Unit 38 ... Evaporator 40 ... Reformer 56 ... Voltage / current monitor 62a to 62c ... Flow sensor

Claims (7)

A fuel cell module having a fuel cell stack in which a plurality of fuel cells that generate electricity by an electrochemical reaction between a fuel gas and an oxidant gas are stacked; and
A control device for controlling the power generation amount of the fuel cell module;
A control method for a fuel cell system comprising:
Fuel gas data and current data corresponding to the target output value of the fuel cell module are preset,
A first step of setting the target output value of the fuel cell module;
A second step of supplying a fuel gas corresponding to the fuel gas data based on the setting result of the first step;
A third step of obtaining a current corresponding to the current data based on the setting result of the first step;
A fourth step of detecting a current output value of the fuel cell module;
A fifth step of comparing the target output value or a specified range of the target output value with the current output value;
A sixth step of adjusting the flow rate of the fuel gas supplied to the fuel cell module;
A seventh step of adjusting a current obtained from the fuel cell module;
An eighth step of updating the fuel gas data corresponding to the target output value;
A ninth step of updating the current data corresponding to the target output value;
Have
A fuel cell system comprising: performing at least one of the sixth step, the seventh step, the eighth step, or the ninth step based on a comparison result of the fifth step. Control method. In the control method according to claim 1, when it is determined in the fifth step that the current output value is less than the target output value or less than a specified range of the target output value.
After increasing the flow rate of the fuel gas supplied to the fuel cell module in the sixth step and then increasing the current obtained from the fuel cell module in the seventh step, the fourth step A control method for a fuel cell system, wherein In the control method according to claim 1 or 2, when it is determined in the fifth step that the current output value exceeds the target output value or exceeds a specified range of the target output value.
The current obtained from the fuel cell module in the seventh step is reduced, and then the flow rate of the fuel gas supplied to the fuel cell module in the sixth step is reduced, and then the fourth step. A control method for a fuel cell system, wherein   The control method according to any one of claims 1 to 3, wherein the sixth step and the seventh step are performed in a state where the fuel utilization rate is maintained within a preset specified range. A control method for a fuel cell system, which is performed. 5. The control method according to claim 1, wherein in the fifth step, the current output value is determined to be equal to or within a specified range of the target output value. When
A method for controlling a fuel cell system, comprising: determining whether or not adjustment has been performed in at least one of the sixth step and the seventh step. In the control method according to claim 5, when it is determined that adjustment is performed at least in any of the sixth step and the seventh step,
A control method for a fuel cell system, wherein at least one of the eighth step and the ninth step is performed.   The control method according to any one of claims 1 to 6, wherein the fuel cell module is a solid oxide fuel cell module.

Images