JP3698101B2 - Control device for fuel reforming fuel cell system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for a fuel reforming fuel cell system.
[0002]
[Prior art]
A fuel reforming fuel cell system is known as one of the fuel cell systems. This fuel reforming fuel cell system generates hydrogen-rich reformed fuel gas by a fuel reformer using methanol or gasoline as fuel, and supplies the reformed fuel gas and air to the fuel cell to extract electric power. Is.
[0003]
In this fuel reforming fuel cell system, when the load suddenly decreases due to a decrease in the load or when the system is stopped, the response of the fuel reformer cannot catch up and excessive reformed fuel gas is generated. There is.
[0004]
Conventionally, as a method for processing such surplus reformed fuel gas, for example, a method of combusting surplus reformed fuel gas by providing a combustor, or a secondary battery in which surplus power is generated by surplus reformed fuel gas is used. (Japanese Patent Application No. 2000-55482, Japanese Patent Application Laid-Open No. 2001-348746, etc.).
[0005]
[Problems to be solved by the invention]
However, when surplus reformed fuel gas is generated in this way, there is a problem that if the surplus reformed fuel gas is burned as it is, the fuel consumption rate of the system deteriorates.
[0006]
On the other hand, when the surplus power is generated and the secondary battery is charged, there is a risk that the upper limit of the charge amount of the secondary battery may be exceeded, so a sufficient charge margin must be prepared.
[0007]
Also, FIG. 11 shows changes in required power, reformed fuel gas amount, generated power, secondary battery charge amount, and reformed fuel gas amount burned by the combustor when the load of the fuel cell system is suddenly reduced. Show. That is, when the required power is drastically reduced as shown in (a), the reformed fuel gas amount changes with a decrease delay as shown in (b), but this reformed fuel as shown in (c). An example in which the surplus amount of gas is used for the power generation of the fuel cell and the amount of charge of the secondary battery exceeds the upper limit value as shown in FIG.
[0008]
In this way, when the upper limit value of the charge amount is exceeded, for example, the generation of surplus power is quickly stopped and the surplus reformed fuel gas is burned in the combustor, but the surplus reformed fuel gas is discharged. On the other hand, since the decrease in the air supply amount to the air electrode (cathode electrode) of the fuel cell is accompanied by a delay, the water in the fuel cell (polymer electrolyte membrane) is wasted (discharged) due to this delay. There is a problem that.
[0009]
An object of the present invention is to appropriately charge a secondary battery with surplus reformed fuel gas generated when the load is suddenly reduced when the load is reduced or the system is stopped in a fuel reforming fuel cell system. It is to be able to process without deteriorating the fuel consumption rate and water consumption.
[0010]
[Means for Solving the Problems]
A first aspect of the present invention is a control device for a fuel reforming fuel cell system including a fuel cell including a reformer, a secondary battery, and a combustor that combusts exhaust gas from the fuel cell. Reformable fuel gas amount estimating means for estimating the amount of generated reformed fuel gas, and electric power generation capability calculation for calculating electric power that can be generated with the reformed fuel gas amount based on the reformed fuel gas amount And a secondary battery charge amount estimating means for estimating a charge amount of the secondary battery, and based on the charge amount, the fuel cell is allowed to generate electric power within a range of a charge limit of the secondary battery. Power generation upper limit power calculation means for calculating an upper limit power, and power generation power calculation means for calculating a power value to be generated by the fuel cell based on the power that can be generated and the power generation upper limit power.
[0011]
According to a second aspect of the present invention, there is provided a control device for a fuel reforming fuel cell system including a fuel cell including a reformer, a secondary battery, and a combustor that combusts exhaust gas from the fuel cell. Reformable fuel gas amount estimating means for estimating the amount of generated reformed fuel gas, and electric power generation capability calculation for calculating electric power that can be generated with the reformed fuel gas amount based on the reformed fuel gas amount Means, power consumption calculating means for calculating power consumption of the electric load, secondary battery charge amount estimating means for estimating the charge amount of the secondary battery, and input to the secondary battery based on the charge amount The secondary battery input possible power calculation means for calculating the possible power, the sum of the secondary battery input power and the power consumption, and the power generation possible power are selected, and the selected one is selected. With the fuel cell as the upper limit Comprising a generated power calculating means for calculating a power value.
[0012]
According to a third invention, in the first and second inventions, there is provided generated power correcting means for correcting a calculated value of the generated power calculating means, wherein the generated power correcting means has a charge amount of the secondary battery within a charging range. This is means for correcting the decrease so that the power generated by the fuel cell becomes smaller as the value approaches the upper limit value.
[0013]
According to a fourth aspect of the present invention, in the first and second aspects of the present invention, the apparatus includes a generated power correction unit that corrects a calculated value of the generated power calculation unit, and the generated power correction unit increases the amount of charge of the secondary battery. This is means for correcting the decrease so that the power generated by the fuel cell becomes smaller as the value of becomes larger.
[0014]
According to a fifth invention, in the first and second inventions, there is provided generated power correcting means for correcting a calculated value of the generated power calculating means, and the generated power correcting means is supplied to the air electrode side of the fuel cell. It is a means for correcting the decrease so that the slower the response of the air amount, the smaller the electric power generated by the fuel cell.
[0015]
According to a sixth aspect of the present invention, in the first and second aspects of the invention, the power generation power correction unit corrects the calculated value of the power generation power calculation unit, and the power generation power correction unit decreases the temperature of the combustor. This is means for correcting the decrease so that the electric power generated by the fuel cell is reduced.
[0016]
According to a seventh invention, in the third to sixth inventions, the generated power correction means includes means for permitting correction when the power that can be generated is larger than the power consumption of the electric load.
[0017]
【The invention's effect】
In the first invention, in the fuel reforming fuel cell system, the amount of reformed fuel gas generated in the fuel reformer is estimated, and electric power that can be generated based on this amount (power that can be generated) Is calculated. On the other hand, the state of charge of the secondary battery is estimated, and based on this, the upper limit power (power generation upper limit power) allowed to be generated by the fuel cell within the range of the secondary battery charge limit is calculated. Since the power generated by the fuel cell is calculated based on the power that can be generated and the power generation upper limit power, if the load on the fuel cell system decreases rapidly and there is no power consumed by the electric load, the power consumption depends on the state of charge of the secondary battery. The power can be generated by the fuel cell and the secondary battery can be charged accurately. Moreover, when the amount of charge of the secondary battery reaches the upper limit by sending surplus reformed fuel gas and air to the combustor, the fuel cell (in the polymer electrolyte membrane) is delayed due to the delay of the decrease in air. Water can be prevented from being wasted (discharged).
[0018]
In the second invention, the power consumption of the electric load is calculated, and the smaller value is selected from the sum of the secondary battery input possible power and the power consumption and the power generation possible power, and the selected value is set as the upper limit. Therefore, when the load of the fuel cell system is drastically reduced, surplus power generated by the surplus reformed fuel gas can be charged within a range in which the secondary battery can be charged. Moreover, when the amount of charge of the secondary battery reaches the upper limit by sending surplus reformed fuel gas and air to the combustor, the fuel cell (in the polymer electrolyte membrane) is delayed due to the delay of the decrease in air. Water can be prevented from being wasted (discharged).
[0019]
In the third aspect of the invention, as the amount of charge of the secondary battery is closer to the upper limit value of the charging range, the power generated by the fuel cell is corrected to decrease so that the power generated by the fuel cell is reduced. By sending surplus reformed fuel gas and air including air to the combustor, it is possible to prevent wasteful consumption (discharge) of water in the fuel cell (in the polymer electrolyte membrane). Also, by starting the combustion of the surplus reformed fuel gas before the charge amount of the secondary battery reaches the upper limit, it is not necessary to complete the combustion of the surplus reformed fuel gas in a short time, so the temperature of the combustor rises. And the capacity of the combustor can be reduced.
[0020]
In the fourth aspect of the invention, the amount of power generated by the fuel cell is corrected so as to decrease as the amount of increase in the amount of charge of the secondary battery increases. The surplus power can be gradually reduced before reaching the upper limit. In addition, the amount of air supplied to the fuel cell can be gradually changed. Therefore, when the charge amount of the secondary battery reaches the upper limit, the inside of the fuel cell (polymer electrolyte membrane) The water inside can be prevented from being wasted (discharged) wastefully. Also, by starting the combustion of the surplus reformed fuel gas before the charge amount of the secondary battery reaches the upper limit, it is not necessary to complete the combustion of the surplus reformed fuel gas in a short time, so the temperature of the combustor rises. And the capacity of the combustor can be reduced.
[0021]
In the fifth aspect of the invention, as the response of the amount of air supplied to the air electrode side of the fuel cell is slower, the generated power of the fuel cell is corrected to decrease so that the power generated by the fuel cell is reduced. In an operating condition in which the response of the amount is slow, the amount of power generation that must be reduced when the upper limit of the charge amount of the secondary battery is reached can be reduced. Therefore, when the charge amount of the secondary battery reaches the upper limit, water in the fuel cell (in the polymer electrolyte membrane) can be prevented from being wasted (discharged) with the delay of the air decrease. Also, by starting the combustion of the surplus reformed fuel gas before the charge amount of the secondary battery reaches the upper limit, it is not necessary to complete the combustion of the surplus reformed fuel gas in a short time, so the temperature of the combustor rises. And the capacity of the combustor can be reduced.
[0022]
In the sixth aspect of the invention, the power generated by the fuel cell is corrected so as to decrease as the temperature of the combustor decreases as the temperature of the combustor decreases. Therefore, the combustor decreases as the temperature of the combustor decreases. The temperature of the combustor can be maintained at an appropriate temperature by increasing the reformed fuel gas to be burned in
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0024]
FIG. 1 is a block diagram showing a fuel cell system according to an embodiment of the present invention.
[0025]
A fuel cell stack 10 according to the embodiment shown in FIG. 1 is mounted at an appropriate position of a vehicle to charge a battery (secondary battery) 11 of an electric vehicle, and a motor 13 of the electric vehicle is connected via a power controller 12. Drive indirectly or directly. This power controller 12 takes out the electric power charged in the battery 11 and supplies it to the motor 13, charges the electric power generated in the fuel cell stack 10 into the battery 11, or generated in the fuel cell stack 10. The electric power is supplied to the motor 13 as it is.
[0026]
In the fuel cell stack 10, hydrogen rich gas is supplied to the fuel electrode (anode electrode) (−), while air from the compressor 21 is supplied to the air electrode (cathode electrode) (+), and cell reaction occurs in the presence of a catalyst. As a result, power is generated. The surplus hydrogen gas and air supplied to the fuel electrode and the air electrode are sent to the combustor 22 for processing.
[0027]
The hydrogen rich gas to be supplied to the fuel electrode of the fuel cell stack 10 can be generated by the reformer 23. The reforming system 20 of this example includes a fuel tank 24 containing a mixed liquid fuel (hereinafter also referred to as a reforming raw material) composed of methanol and an excess amount of water, a reformer 23, and carbon monoxide removal. A combustor 25 and a combustor 22.
[0028]
While the reforming raw material in the fuel tank 24 is sent to the reformer 23 using the pump 26, air as an oxidant is sent from the compressor 21. Then, the reformed gasified raw material is subjected to a reforming reaction in the presence of the reforming catalyst to generate a reformed gas containing hydrogen and carbon dioxide.
[0029]
A carbon monoxide remover 25 provided downstream of the reformer 23 selectively oxidizes carbon monoxide contained in the reformed gas by introducing air from the compressor 21, and poisons the fuel cell stack 10. This is to reduce the concentration of carbon monoxide that causes the above. The reformed gas thus rich in hydrogen is supplied to the fuel electrode of the fuel cell stack 10.
[0030]
In the combustor 22, the reformed gas and air surplus in the fuel cell stack 10 are combusted in the presence of the combustion catalyst, and the combustion energy at this time is supplied to the reformer 23, thereby reforming at the same time as the exhaust gas treatment. Has the function of promoting the reaction.
[0031]
The temperature sensor T1 is in the reformer 23, the temperature sensor T2 is in the outlet pipe of the reformer 23, the temperature sensor T3 is in the carbon monoxide remover 25, and the temperature sensor is in the outlet pipe of the carbon monoxide remover 25. T4 is provided, and these detection signals are sent to the reformer controller 30. A pressure sensor P1 is provided at the outlet pipe of the fuel electrode of the fuel cell stack 10, and this detection signal is sent to the stack controller 31 of the power control device.
[0032]
Control valves 14 and 15 are provided at the fuel electrode outlet pipe and the air electrode outlet pipe of the fuel cell stack 10, respectively.
[0033]
The reformer control device 30 responds to a command signal corresponding to an external load such as an accelerator or the like, and inputs the reforming raw material from the fuel tank 24 to the reformer 23 and the air supply amount from the compressor 21. The amount of hydrogen-rich gas to be supplied to the fuel cell stack 10 is controlled.
[0034]
The stack controller 31 of the power control device calculates and controls the power value generated by the fuel cell stack 10 based on the amount of hydrogen-rich gas generated, the amount of charge for the battery 11 and the electric load such as the motor 13. . In addition, the stack controller 31 of the power control device controls the amount of hydrogen gas and the amount of air that are surplus in the fuel cell stack 10 and sent to the combustor 22 via the control valves 14 and 15.
[0035]
The battery monitor 32 of the power control device monitors the charge amount (storage amount) of the battery 11 and the charge margin amount (how much charge can be performed with respect to the charge amount of the battery 11). The charge amount and charge margin of the battery 11 are, for example, an integrated value (= Σ (I × t): I is a current value obtained by integrating the battery capacity experimentally obtained in advance and the current during charging / discharging. Known methods such as a method of calculating from t) and a method of calculating from the relationship with the open-circuit voltage can be adopted.
[0036]
Next, the operation will be described.
[0037]
2 and 3 are flowcharts showing the operation of the control device (power control device) of the present invention. This is executed at a predetermined control cycle.
[0038]
In Step 1 of FIG. 2, the reformed fuel gas (hydrogen) generation amount Qh [mol / sec] is estimated (calculated) with respect to the reforming raw material input amount Qf [l / sec] using the following equation. . In the following equation, Kr is a coefficient corresponding to the amount of reformed fuel gas [mol] that can be generated from the reforming raw material 1 [l], and ηr is a coefficient that represents the efficiency of the reformer 23. Tr is a response time constant [sec] of the reformer 23, and s is a Laplace operator.
[0039]
Qh = Qf × Kr × ηr / (Trs + 1)
In step 2, a current Ih [A] that can be taken out from the fuel cell stack 10 is calculated according to the following equation based on the estimated reformed fuel gas amount Qh.
[0040]
Ih = Qh / (2 × F × Sr)
Here, F is the Faraday constant, and Sr is the hydrogen excess rate of the fuel cell stack 10.
[0041]
Then, electric power Ph [kW] that can be generated by the fuel cell stack 10 is calculated according to the following equation.
[0042]
Ph = Ih × Eh
Here, Eh is the voltage of the fuel cell stack 10 and is calculated by referring to, for example, table data having the characteristics shown in FIG. 4 based on the extracted current Ih.
[0043]
In step 3, the battery monitor 32 of the power control apparatus estimates (calculates) a charge margin amount Wb [kWh] of the battery 11. The method for estimating the charge margin of the battery 11 is as described above.
[0044]
In step 4, first, electric power Pb [kW] that can be input to the battery 11 is calculated. This calculation is performed, for example, by referring to the table data having the characteristics shown in FIG. 5 based on the charge margin Wb [kWh] of the battery 11.
[0045]
Next, the power consumption of the electric load is calculated. As the power consumption of the electric load, the power consumption Pm [kW] of the motor 13 for driving the electric vehicle is calculated according to the following equation.
[0046]
Pm = Im × Em
Here, Im is a current [A] flowing through the motor 13, and Em is a voltage [V] of the motor 13.
[0047]
Then, the power generation upper limit power Pmax [kW] of the fuel cell stack 10 is calculated by adding the power Pb [kW] that can be input to the battery 11 and the power consumption Pm [kW] of the motor 13.
[0048]
When there is no power consumption Pm [kW] of the motor 13, the power Pb [kW] that can be input to the battery 11 is allowed to generate power in the fuel cell stack 10 within the range of the charging limit of the battery 11. The upper limit power, that is, the power generation upper limit power Pmax [kW] of the fuel cell stack 10 is obtained.
[0049]
In step 5, the electric power Pg [kW] generated by the fuel cell stack 10 is calculated according to the flowchart shown in FIG.
[0050]
First, in step 11, a value having a small value is selected from the electric power Ph [kW] that can be generated by the fuel cell stack 10 and the power generation upper limit power Pmax [kW] of the fuel cell stack 10, and the value is selected as the fuel cell stack. A reference value Pg0 [kW] of 10 generated power is assumed.
[0051]
In step 12, the power generation possible power Ph [kW] of the fuel cell stack 10 and the power consumption Pm [kW] of the motor 13 are compared.
[0052]
If the power generation possible power Ph [kW] of the fuel cell stack 10 is larger, the reduction correction coefficient α is calculated in steps 13 and 14, and the generated power reference value Pg0 [kW] is reduced and corrected to generate power Pg. Calculate [kW].
[0053]
The decrease correction coefficient α is calculated with reference to table data as shown in FIG. 6 based on the charge margin amount Wb [kWh] of the battery 11 estimated in step 4 of FIG. That is, the correction is performed so that the power Pg [kW] generated by the fuel cell stack 10 decreases as the charge amount of the battery 11 approaches the upper limit value of the charging range.
[0054]
On the other hand, if the power generation possible power Ph [kW] of the fuel cell stack 10 is smaller, the power generation possible power Ph [kW] is not corrected in step 15 without correcting the power generation power reference value Pg0 [kW]. Generated power Pg [kW].
[0055]
In addition to the motor 13, an electric load such as an air conditioner or a radiator fan provided in the electric vehicle may be applied as the electric load.
[0056]
With such a configuration, when the load of the fuel cell system is suddenly reduced and surplus reformed fuel gas is generated (power generation possible power Ph [kW] of the fuel cell stack 10> power consumption Pm [kW] of the motor 13), Power generation is performed in the fuel cell stack 10 by the surplus reformed fuel gas, and in this case, when there is no power consumption Pm [kW] of the motor 13, power generation is performed in the fuel cell stack 10 within the range of the charging limit of the battery 11. Is set to the generated power reference value Pg0 [kW] of the fuel cell stack 10, and this is corrected to decrease as the charge amount of the battery 11 approaches the upper limit value of the charging range, and the fuel cell stack 10 generates power. The electric power Pg [kW] to be obtained is obtained, and surplus hydrogen gas and air including the decrease correction amount are sent to the combustor 22 so as to obtain the generated electric power Pg [kW].
[0057]
As a result, the fuel cell stack 10 can generate electric power according to the state of charge of the battery 11, and the battery 11 can be charged accurately. Further, as the charged amount of the battery 11 is closer to the upper limit value of the charging range, the power Pg [kW] generated by the fuel cell stack 10 is corrected to decrease, and surplus hydrogen gas and air including the decreased correction amount are combusted. Therefore, the reduction of air is not delayed compared to the case where surplus hydrogen gas and air are sent to the combustor 22 after the charge amount of the battery 11 reaches the upper limit value. Thus, it is possible to prevent wasteful consumption (discharge) of water in the fuel cell (in the polymer electrolyte membrane).
[0058]
In this case, when the power consumption Pm [kW] of the motor 13 is present, the fuel cell stack 10 is obtained by adding the power Pb [kW] that can be input to the battery 11 and the power consumption Pm [kW] of the motor 13. The power generation upper limit power Pmax [kW] of the fuel cell stack 10 and the power generation possible power Ph [kW] of the fuel cell stack 10 are selected as the power generation reference value Pg0 [kW] of the fuel cell stack 10, and this is used as the battery. 11 is corrected to decrease as the charge amount approaches the upper limit value of the charging range, power Pg [kW] generated by the fuel cell stack 10 is obtained, and the decrease correction amount is set so as to obtain this generated power Pg [kW]. The surplus hydrogen gas and air included are sent to the combustor 22.
[0059]
Thus, surplus power generated by the surplus reformed fuel gas can be charged within a range in which the battery 11 can be charged. Further, as the charged amount of the battery 11 is closer to the upper limit value of the charging range, the power Pg [kW] generated by the fuel cell stack 10 is corrected to decrease, and surplus hydrogen gas and air including the decreased correction amount are combusted. 22, as in the case where there is no power consumption Pm [kW] of the motor 13, for example, in the fuel cell (in the polymer electrolyte membrane) due to the delay of air decrease after the charge amount of the battery 11 reaches the upper limit value. ) Can be prevented from being wasted (discharged).
[0060]
FIG. 7 shows the required power (power consumption Pm [kW] of the motor 13), the reformed fuel gas amount, the generated power, the charge amount of the battery 11, and the combustor when the load of the fuel cell system in this example is suddenly reduced. 22 is a graph showing changes in the amount of reformed fuel gas burned at 22. Since the surplus reformed fuel gas is used for power generation within a range in which the battery 11 can be charged, the energy of the surplus reformed fuel gas is supplied to the battery 11 while preventing the charged amount of the battery 11 from exceeding the upper limit. Can be stored. Further, as the charged amount of the battery 11 is closer to the upper limit value of the charging range, the power Pg [kW] generated by the fuel cell stack 10 is corrected to decrease, and surplus hydrogen gas and air including the decreased correction amount are combusted. Therefore, it is possible to prevent wasteful consumption (discharge) of water in the fuel cell (in the polymer electrolyte membrane). Further, since the combustion of the surplus reformed fuel gas is started before the amount of charge of the battery 11 reaches the upper limit, it is not necessary to complete the combustion of the surplus reformed fuel gas in a short time. In addition, the capacity of the combustor 22 can be reduced.
[0061]
8, 9, and 10 show the second, third, and fourth embodiments of the calculation method of the decrease correction coefficient α of the electric power Pg [kW] generated by the fuel cell stack 10.
[0062]
In FIG. 8, the decrease correction coefficient α is set based on the change amount of the charge margin of the battery 11, and the change amount ΔWb [kWh / sec] of the charge margin amount Wb [kWh] of the battery 11 is calculated. Then, based on the change amount ΔWb [kWh / sec], the reduction correction coefficient α is obtained with reference to the table data set as shown in FIG. That is, the correction is performed so that the power Pg [kW] generated by the fuel cell stack 10 decreases as the increase in the charge amount of the battery 11 increases.
[0063]
According to this, the surplus power can be gradually reduced until the charge amount of the battery 11 reaches the upper limit. In addition, the amount of air supplied to the fuel cell can be gradually changed. Therefore, when the charge amount of the battery 11 reaches the upper limit, the fuel cell (inside the polymer electrolyte membrane) ) Can be prevented from being wasted (discharged). Further, since the combustion of the surplus reformed fuel gas is started before the amount of charge of the battery 11 reaches the upper limit, it is not necessary to complete the combustion of the surplus reformed fuel gas in a short time. In addition, the capacity of the combustor 22 can be reduced.
[0064]
9 refers to the table data set as shown in FIG. 9 based on the response time constant τ [sec] of the amount of air supplied to the air electrode (cathode electrode) of the fuel cell stack 10. Then, a decrease correction coefficient α is calculated. That is, the correction is performed so that the power Pg [kW] generated by the fuel cell stack 10 becomes smaller as the response time constant τ [sec] of the supply air amount is slower. Here, since the response time constant τ of the air amount changes according to the operating pressure of the fuel cell and the supply air amount, the change of the response time constant with respect to these conditions is obtained experimentally, and the table data or the three-dimensional map The response time constant τ [sec] can be calculated using data or the like.
[0065]
This makes it possible to reduce the amount of power generation that must be reduced when the charge amount of the battery 11 reaches the upper limit under operating conditions in which the response of the supply air amount is slow. Therefore, when the charge amount of the battery 11 reaches the upper limit, it is possible to prevent the water in the fuel cell (in the polymer electrolyte membrane) from being consumed (discharged) in vain with the delay of the air decrease. Further, since the combustion of the surplus reformed fuel gas is started before the charge amount of the battery 11 reaches the upper limit, it is not necessary to complete the combustion of the surplus reformed fuel gas in a short time. In addition, the capacity of the combustor 22 can be reduced.
[0066]
In FIG. 10, the reduction correction coefficient α is calculated based on the temperature Tb [degC] of the combustor 22 with reference to table data as shown in FIG. That is, the correction is performed so that the electric power Pg [kW] generated by the fuel cell stack 10 decreases as the temperature Tb [degC] of the combustor 22 decreases. Therefore, the lower the temperature of the combustor, the more the reformed fuel gas burned in the combustor can be increased, and the temperature of the combustor can be maintained at an appropriate temperature.
[Brief description of the drawings]
FIG. 1 is a block diagram of a fuel cell system showing a first embodiment.
FIG. 2 is a flowchart showing control contents.
FIG. 3 is a flowchart showing control contents.
FIG. 4 is a diagram showing characteristics of table data for calculating a voltage of a fuel cell.
FIG. 5 is a diagram illustrating characteristics of table data for calculating electric power that can be input to the secondary battery.
FIG. 6 is a diagram showing characteristics of table data for calculating a coefficient for correcting the generated power of the fuel cell.
FIG. 7 is a graph showing changes in required power, reformed fuel gas amount, generated power, secondary battery charge amount, and reformed fuel gas amount combusted in a combustor when the load of the fuel cell system is suddenly reduced. It is.
FIG. 8 is a diagram illustrating characteristics of table data for calculating a coefficient for correcting the generated power of the fuel cell according to the second embodiment.
FIG. 9 is a diagram showing characteristics of table data for calculating a coefficient for correcting the generated power of the fuel cell according to the third embodiment.
FIG. 10 is a diagram showing characteristics of table data for calculating a coefficient for correcting the generated power of the fuel cell according to the fourth embodiment.
FIG. 11 shows changes in required power, reformed fuel gas amount, generated power, secondary battery charge amount, and reformed fuel gas amount burned in a combustor when the load of the conventional fuel cell system is suddenly reduced. It is the shown graph.
[Explanation of symbols]
10 Fuel cell stack
11 Battery (secondary battery)
13 Motor
14,15 Control valve
21 Compressor
22 Combustor
23 reformer
24 Fuel tank
30 Reformer control device
31 Stack controller
32 battery monitor

Claims (7)

In a control device for a fuel cell and a secondary battery including a reformer, and a fuel reforming fuel cell system including a combustor that combusts exhaust gas of the fuel cell,
Based on the reformed fuel gas amount estimating means for estimating the reformed fuel gas amount generated by the reformer, and calculating electric power that can be generated with the reformed fuel gas amount based on the reformed fuel gas amount Power generation possible electric power calculation means,
Secondary battery charge amount estimating means for estimating the charge amount of the secondary battery;
A power generation upper limit power calculating means for calculating an upper limit power allowed to be generated by the fuel cell within a range of a charge limit of the secondary battery based on the charge amount;
A control device for a fuel reforming fuel cell system, comprising: generated power calculation means for calculating a power value generated by the fuel cell based on the power that can be generated and the power generation upper limit power. In a control device for a fuel cell and a secondary battery including a reformer, and a fuel reforming fuel cell system including a combustor that combusts exhaust gas of the fuel cell,
Based on the reformed fuel gas amount estimating means for estimating the reformed fuel gas amount generated by the reformer, and calculating electric power that can be generated with the reformed fuel gas amount based on the reformed fuel gas amount Power generation possible electric power calculation means,
Power consumption calculating means for calculating the power consumption of the electrical load;
Secondary battery charge amount estimating means for estimating the charge amount of the secondary battery;
A secondary battery input possible power calculating means for calculating power that can be input to the secondary battery based on the charge amount;
A power generation calculation for calculating a power value to be generated by the fuel cell with the selected value as an upper limit by selecting the smaller value from the sum of the secondary battery input power and the power consumption and the power generation possible power And a control device for the fuel reforming type fuel cell system. The generated power correcting means corrects the calculated value of the generated power calculating means, and the generated power correcting means increases the amount of power generated by the fuel cell as the charge amount of the secondary battery is closer to the upper limit value of the charging range. 3. The control device for a fuel reforming fuel cell system according to claim 1, wherein the control device is a means for correcting the decrease so as to decrease. The generated power correction means corrects the calculated value of the generated power calculation means, and the generated power correction means decreases the power generated by the fuel cell as the amount of increase in the charge amount of the secondary battery increases. 3. The control device for a fuel reforming fuel cell system according to claim 1, wherein the control device is a means for correcting the decrease. The generated power correcting means corrects the calculated value of the generated power calculating means, and the generated power correcting means generates power by the fuel cell as the response of the amount of air supplied to the air electrode side of the fuel cell is slower. 3. The control device for a fuel reforming fuel cell system according to claim 1 or 2, wherein the control device is a means for correcting the decrease so as to decrease. The power generation correction unit includes a power generation correction unit that corrects a calculation value of the power generation calculation unit, and the power generation correction unit corrects the decrease so that the power generated by the fuel cell decreases as the temperature of the combustor decreases. 3. The control device for a fuel reforming fuel cell system according to claim 1, wherein the control device is a fuel reforming fuel cell system. The fuel according to any one of claims 3 to 6, wherein the generated power correcting means includes means for permitting correction when the power that can be generated is larger than the power consumed by the electric load. A control device for a reforming fuel cell system.

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