JP2001338659A - Fuel cell system and temperature control method of reforming equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell system having a good response to a temperature control of a reforming equipment. SOLUTION: The fuel cell system is comprised of a reforming equipment temperature detection means 9 to detect the temperature of the reforming equipment 1, 2, a reforming equipment temperature control means 23 to control an opening degree of a bulb 7 for an anode side pressure adjustment of the fuel cell main body 3, so that an actual temperature of the reforming equipment detected with the reforming equipment temperature detection means may turn into a target temperature, a pressure detection means 20 to detect a pressure of the anode side entrance of the fuel cell main body 3, a pressure detection means 22 to detect a pressure of cathode side entrance of the fuel cell main body 3, and cathode side pressure control means 24, 25 to control the pressure of the cathode side entrance of the fuel cell main body based on the actual pressure detected with these two pressure detection means 20, 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell system and a method for controlling the temperature of a reformer, and more particularly, to a fuel cell system having good responsiveness of temperature control of a reformer and a reformer having excellent responsiveness. It relates to a temperature control method.

[0002]

2. Description of the Related Art In a fuel cell power generator, a reformer for producing a reformed gas having a high hydrogen concentration by reforming a hydrocarbon material such as methanol, a reformed gas generated by the reformer, Separately, a fuel cell body that generates electricity by reacting with oxygen gas in the air supplied from an air supply device such as a compressor, and a heat evaporator that heats and evaporates hydrocarbon materials such as methanol And the combustor that supplies the fuel to the main components. Then, the raw fuel evaporated in the raw material evaporating section is led to a catalyst for performing a reforming reaction provided inside the reformer, whereby a reformed gas having a high hydrogen concentration is generated.

[0003] In a so-called autothermal reformer, a steam reforming reaction (endothermic reaction) for generating a reformed gas having a high hydrogen concentration and a partial oxidation reaction for covering the calorie required for the steam reforming reaction are performed. Both reactions (exothermic reaction) proceed. At this time, in order to raise the temperature of the entire reforming reaction, a partial oxidation reaction which is an exothermic reaction is promoted. That is, the proportion of the steam reforming reaction that generates the reformed gas in the catalyst inside the reformer is relatively reduced.

On the other hand, in order to lower the temperature of the whole reforming reaction, the rate of the partial oxidation reaction on the catalyst inside the reformer is relatively reduced by promoting the endothermic steam reforming reaction. I do.

Here, the ratio of the partial oxidation reaction occupying on the catalyst inside the reformer can be changed by the amount of the oxidizing agent supplied to the reformer. As the oxidizing agent, oxygen gas in the air supplied from an air supply device provided separately from the reformer is generally used, so the temperature of the reformer is controlled by controlling the flow rate of this air. can do.

As a conventional temperature control method for a reformer, an operation amount of an air supply device is calculated so that the temperature of the reformer measured by a temperature sensor becomes a target temperature, and the air supply device is controlled. For example, Japanese Patent Application Laid-Open No. 7-2968
No. 34 is reported.

[0007] A valve for adjusting the air flow rate is provided at the inlet of the reformer, and the valve opening is controlled so that the temperature of the reformer measured by the temperature sensor becomes a target temperature. For example, it is reported in JP-A-11-130403.

[0008]

However, since the reformer is operated under pressure, the conventional control method described above requires time until the flow rate of air flowing into the reformer reaches the target air flow rate. And the response of the temperature control of the reformer is poor.

That is, the pressure of the reformer is usually controlled by a pressure regulating valve which is separately provided. However, when the opening of the air supply device or the air flow regulating valve is adjusted to increase or decrease the flow rate of air, the reforming is performed. The pressure inside the vessel will also change. In response to this, it is necessary to readjust the pressure regulating valve to keep the pressure inside the reformer constant, and this also changes the pressure inside the reformer, so that it flows into the reformer. The air flow needs to be changed again.
That is, since such control is repeated endlessly, it takes time until the air flow rate flowing into the reformer reaches the target air flow rate, which causes a problem that the temperature control response of the reformer is slow.

[0010] The present invention has been made in view of such problems of the prior art, and has a fuel cell system with good responsiveness of temperature control of a reformer and a temperature of a reformer with excellent responsiveness. It is an object to provide a control method.

[0011]

(1) In order to achieve the above object, according to a first aspect of the present invention, an oxidant supply means for supplying an oxidant to a fuel cell system, and the oxidant supply Supplying the oxidant supplied from the means to the reformer
An oxidizing agent supply system, a second oxidizing agent supplying system for supplying an oxidizing agent supplied from the oxidizing agent supplying means to a cathode side of a fuel cell body, And a source gas supplied from the oxidant supply unit, wherein the source gas supplied from the source gas supply unit is reformed by a catalyst layer provided therein to generate a hydrogen-containing reformed gas, and supplied from the oxidant supply unit. A reformer that performs a partial oxidation reaction of the oxidant to be performed with a catalyst layer provided therein to obtain a calorie necessary for the reforming reaction, and the reformed gas is supplied to the anode side, and is supplied from the oxidant supply unit. An oxidizing agent is supplied to the cathode side, and a fuel cell body for generating electricity, and an anode-side pressure adjusting valve provided in an exhaust reformed gas system at an anode-side outlet of the fuel cell body to adjust the anode-side pressure, , The fuel cell body catho In a fuel cell system having a cathode-side pressure adjusting valve provided in a side outlet exhaust oxidizer system and adjusting a cathode-side pressure, a reformer temperature detecting means for detecting a temperature of the reformer, Reformer temperature control means for controlling the opening of the anode-side pressure regulating valve of the fuel cell body, so that the actual temperature of the reformer detected by the reformer temperature detection means becomes the target temperature, Pressure detecting means for detecting the pressure at the anode inlet of the fuel cell body, pressure detecting means for detecting the pressure at the cathode inlet of the fuel cell body, and the actual pressure detected by these two pressure detecting means. And a cathode-side pressure control means for controlling a pressure at a cathode-side inlet of the fuel cell main body based on the fuel cell system (see claim 1).

Further, according to a second aspect of the present invention, by adjusting the difference between the pressure on the cathode side of the fuel cell and the pressure on the anode side of the fuel cell, the pressure on the inlet side of the reformer is reduced. A temperature control method for a reformer, comprising: controlling a temperature of the reformer by adjusting a difference between the pressure at the outlet side of the reformer and a flow rate of the oxidant flowing into the reformer. (See claim 5).

According to the present invention, in order to control the flow rate of the oxidant such as air flowing into the reformer, the valve opening for adjusting the pressure on the anode side of the fuel cell main body into which the reformed gas such as hydrogen gas is introduced. Control.

That is, when increasing the flow rate of the oxidizing agent, the pressure on the anode side is controlled to be lower than the current value, and when decreasing the air flow rate, the pressure on the anode side is controlled to be higher than the current value. This allows the flow rate of the oxidant flowing into the reformer to quickly reach the target flow rate, and improves the temperature control response performance of the reformer.

Further, the valve opening for adjusting the pressure on the cathode side of the fuel cell body is controlled so that the pressure on the cathode side of the fuel cell body becomes higher than the pressure on the anode side by a predetermined value. By doing so, the flow rate of the oxidizer in the reformer can be quickly controlled to the target value while maintaining the pressure difference between the anode and the cathode of the fuel cell at a predetermined value, and the temperature control response of the reformer can be controlled. Performance is improved.

(2) In the above invention, although not particularly limited, the cathode side pressure control means makes the target value of the pressure at the cathode side inlet higher by a predetermined value than the output of the anode side inlet pressure detecting means. Thus, by adding a predetermined value to the output value of the anode side inlet pressure detection means,
A target value calculating means for calculating a target value of the pressure at the cathode side inlet, such that an actual pressure detected by the cathode side inlet pressure detecting means becomes a target value calculated by the target value calculating means. It is more preferable to control the opening of the cathode-side pressure regulating valve (see claim 2).

According to this invention, the inlet pressure on the cathode side of the fuel cell can always be higher than the pressure on the anode side, and the reformed gas on the anode side of the fuel cell flows back toward the reformer. Can be prevented. Further, the pressure difference between the cathode side and the anode side can always be controlled within a predetermined range allowed in the fuel cell body.

(3) In the above invention, although not particularly limited, the reformer temperature control means calculates an anode side target pressure based on a required value of the load power of the fuel cell body. Pressure calculation means, target oxidant flow rate calculation means for calculating a target value of the total oxidant flow rate to be supplied by the oxidant supply means based on the required value of the load power, and a target value of the anode side inlet pressure. A pressure comparison unit that compares the output value of the anode-side inlet pressure detection unit, and an output value of the anode-side inlet pressure detection unit that deviates from an upper limit or a lower limit of a target value of the anode-side inlet pressure. Is a pressure feedback control means for calculating a correction value of the oxidant flow rate such that the actual pressure detected by the anode-side inlet pressure detection means becomes the target value of the anode-side inlet pressure. When, and more preferably contains a target oxidizer flow rate correction means for correcting the target value of the total oxidant flow rate based on the correction value of the oxidizing agent flow rate by the pressure feedback correction means (see claim 3).

According to the present invention, when the pressure on the anode side of the fuel cell exceeds the upper limit, the corrected oxidant flow rate is calculated so as to reduce the total oxidant flow rate, and the total oxidant flow rate is reduced. Can be made to act so that the pressure on the anode side becomes smaller than the upper limit value. When the pressure on the anode side exceeds the lower limit value, the corrected oxidant flow rate can be calculated so as to increase the total oxidant amount, and the total oxidant flow rate can be increased. It can work to be larger. Thus, the pressure on the anode side can be controlled so as to be within the range of the upper and lower limit values of the target pressure.

(4) Although not particularly limited in the above invention, the reformer temperature control means calculates a target temperature of the reformer based on a required value of load power of the fuel cell body. Target temperature calculating means, a reformer target oxidant flow rate calculating means for calculating a target value of an oxidant flow rate to be supplied to the reformer based on a required value of load power of the fuel cell main body, The calculated target oxidant flow rate is set such that the actual temperature detected by the reformer temperature detection means becomes the target temperature with respect to the target oxidant flow rate calculated by the target oxidant flow rate calculation means. It is more preferable to include a correction means for correcting (refer to claim 4).

According to the present invention, the target oxidant flow rate to be supplied to the reformer, which is calculated based on the required value of the load power of the fuel cell, is controlled by the oxidant required by the temperature control of the reformer. The flow rate can be corrected and added for control.

The target oxidant flow rate to be supplied to the reformer calculated based on the required value of the load power of the fuel cell is:
The calculation is performed so that the reformer does not run away and break the balance of the operation of the entire fuel cell system. For this reason, the temperature of the reformer should be the target temperature if the target oxidant flow rate can be controlled, but when calculating the target oxidant flow rate, it is actually assumed due to assumed or simplified characteristics. It may cause a gap. According to the second aspect of the present invention, it is possible to control the temperature of the reformer while correcting the deviation, and to control the fuel cell system without greatly disturbing the operation balance.

[0023]

According to the first and fifth aspects of the present invention,
While maintaining the pressure difference between the anode and the cathode of the fuel cell at a predetermined value, the flow rate of the oxidant in the reformer can be quickly controlled to the target value, and the temperature control response performance of the reformer is improved.

In addition to the above, according to the second aspect of the invention, the reformed gas on the anode side of the fuel cell can be prevented from flowing back toward the reformer, and the pressure difference between the cathode side and the anode side can be prevented. Can always be controlled within a predetermined range allowed by the fuel cell body. Furthermore, the temperature of the reformer can be controlled while correcting the deviation when calculating the target oxidant flow rate, and the control can be performed without significantly disturbing the operation balance of the entire fuel cell system.

According to the third aspect of the present invention, the pressure on the anode side can be controlled so as to fall within the range of the upper and lower limits of the target pressure.

According to the fourth aspect of the present invention, it is possible to correct and add the oxidant flow rate required for the temperature control of the reformer to the target oxidant flow rate for control.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a fuel cell system of the present invention (corresponding to claims), FIG. 2 is a block diagram for explaining the control contents of the reformer temperature control means shown in FIG. 1, and FIG. FIG. 4 is a block diagram for explaining another control content of the temperature control means, and FIG. 4 is a block diagram showing a specific example of the fuel cell system of the present invention shown in FIG.
Hereinafter, the configuration of the higher concept shown in FIGS. 1 to 3 and the configuration of the lower concept shown in FIG. 4 will be described in comparison.

As shown in FIG. 1, the fuel cell system according to this embodiment supplies oxidant to the fuel cell system with oxidant supply means 4 (air supply device 4 in FIG. 4). The supplied oxidant is supplied to the reformers 1 and 2
A first oxidant supply system 51 for supplying to the reformers 1 and 2 in FIG. 4 and an oxidant supplied from the oxidant supply means 4 are supplied to the fuel cell main body 3 (the fuel cell main body 3 in FIG. 4). A second oxidant supply system 52 for supplying to the cathode side, and source gas supply means 11, 12, 15 to 18 for supplying source gas obtained by evaporating the raw fuel to the reformers 1 and 2 (flow rate control in FIG. 4). Valves 11 and 12, water source tank 15, methanol source tank 16, flow controllers 17 and 18), and a catalyst layer provided therein with source gases supplied from source gas supply means 11, 12, 15 to 18 A reforming reaction is performed to generate a hydrogen-containing reformed gas, and an oxidizing agent supplied from the oxidizing agent supply unit 4 is partially oxidized by a catalyst layer provided therein to obtain a heat amount necessary for the reforming reaction. And reformer gas are supplied to the anode side At the same time, the oxidant from the oxidant supply means 4 is supplied to the cathode side to be provided to the fuel cell main body 3 for generating electric power and the exhaust reformed gas system 54 at the anode side outlet of the fuel cell main body 3, and the pressure on the anode side Pressure regulating valve 7 (anode pressure regulating valve 7 in FIG. 4) for regulating the pressure, and a cathode side pressure provided on exhaust oxidant system 53 at the cathode side outlet of fuel cell body 3 for regulating the cathode side pressure And a regulating valve 6 (a cathode pressure regulating valve 6 in FIG. 4).

Further, the fuel cell system according to the present embodiment includes a reformer temperature detecting means 9 (reformed gas temperature detecting device 9 in FIG. 4) for detecting the temperatures of the reformers 1 and 2, Reformer temperature control means 23 for controlling the opening of the anode-side pressure regulating valve 7 of the fuel cell body 3 so that the actual temperatures of the reformers 1 and 2 detected by the detection means 9 become the target temperature. (In FIG. 4, the reformer temperature control means 23), the pressure detecting means 20 for detecting the pressure at the anode inlet of the fuel cell main body 3 (the pressure detecting device 20 in FIG. 4), and the cathode inlet of the fuel cell main body 3 The pressure at the cathode side of the fuel cell body 3 is determined based on the actual pressure detected by the pressure detecting means 22 (pressure detecting device 22 in FIG. 4) and the two pressure detecting means 20 and 22. Cathode side pressure to control And a control means 24, 25 (the target pressure calculating means 24 and the pressure control means 25 in FIG. 4).

As shown in FIG. 4, the reformer includes an evaporating section 1 for reforming a raw material to generate a reformed gas and a reforming catalyst section 2. The used raw material is evaporated using heat supplied from the combustor 8. The raw material turned into steam in the evaporating section 1 is led to the reforming catalyst section 2 of the reformer and reformed. In the present embodiment, the evaporating unit 1 and the reforming catalyst unit 2 are collectively referred to as a reformer.

In the reforming catalyst section 2, the raw material evaporated in the evaporating section 1 of the reformer is reacted with oxygen in the air from the air supply device 4, and a partial oxidation reaction, which is an exothermic reaction, A steam reforming reaction for producing a reformed gas having a high concentration is performed. This reformer is a so-called autothermal reformer,
The heat generated by the partial oxidation reaction is used to cover the endothermic component of the steam reforming reaction.

Water and methanol are used as raw materials to be supplied to the reformer 1 and are supplied to the evaporating section 1 of the reformer through flow control valves 11 and 12, respectively. The flow rate of water is adjusted by a flow control valve 11, and water as a raw material is supplied from a water raw material tank 15. Similarly, the flow rate of methanol is adjusted by the flow control valve 12, and the raw material methanol is supplied from a methanol raw material tank 16. The target value calculating means 13 is a device for calculating the required flow rates of methanol and water from the electric power required for the fuel cell main body 3, respectively. It is input to the flow controllers 17 and 18 as a target flow rate.
Then, the flow controllers 17 and 18 calculate the target openings of the flow control valves 11 and 12 from the respective target flows and control the respective valve openings.

The hydrogen-rich reformed gas generated in the reforming catalyst section 2 of the reformer is led to the anode of the fuel cell body 3. The cathode of the fuel cell 3 is provided with an air supply device 4.
From the air, and the oxygen component reacts with the hydrogen component in the reformed gas supplied to the anode to generate power. Note that the air supply device 4 of the present embodiment is a compressor.

The current generated by the fuel cell body 3 is equal to the load 2
The reformed gas and air consumed by the fuel cell body 6 but not consumed by the fuel cell body 3 are respectively discharged as exhaust gas.
That is, the exhaust reformed gas is exhausted through the anode pressure regulating valve 7, and the exhaust air is exhausted through the cathode pressure regulating valve 6. The anode pressure adjusting valve 7 has a function of adjusting the pressure of the reformed gas system from the reformers 1 and 2 to the fuel cell body 3. The opening of the anode pressure regulating valve 7 is controlled by the output of the reformer temperature control means 23.

On the other hand, the cathode pressure adjusting valve 6 has a function of adjusting the pressure of the air system from the air supply device 4 to the fuel cell body 3. The opening of the cathode pressure regulating valve 6 is controlled by the output of the pressure control means 25.

In FIG. 4, "5" is a control device for controlling the flow rate of the air supplied to the fuel cell body 3, and outputs the output of the air flow detection device 21 and the target air flow to the air flow control device 5. By inputting the calculated value, the target compressor speed is calculated, and the compressor speed is controlled so that the actual air flow rate becomes the target flow rate.

Exhaust air and exhaust reformed gas from the fuel cell main body 3 pass through an exhaust gas supply system 27 and are burned in a combustor 8, and the combustion heat generated in the combustor 8 is transmitted to an evaporator 1 of the reformer. Used. In FIG. 4, "14" denotes a combustor temperature controller for controlling the outlet temperature of the combustor 8 to the target temperature, and controls the air flow regulating valve 10 so that the output of the combustor outlet gas temperature detector 19 becomes the target temperature. The opening is controlled to adjust the flow rate of air from the air supply device 4 to the combustor 8.

Next, the control contents of the reformer temperature control means 23 will be described with reference to FIG. Reformer temperature control means 2
In 3, the output t of the reformer gas temperature detector 9 is
Is calculated by the temperature feedback control means 231 so that the air flow rate ΔQ required for the reformer temperature control is set so that the target temperature T0 becomes the reformer target temperature T0. This reformer target temperature T0
Is calculated by the target value calculating means 13 which calculates a target value according to the load electric energy required for the fuel cell system. In the embodiment, the temperature control of the reformers 1 and 2 is performed at the reformer outlet gas temperature by the reformer gas temperature detector 9, but the gas temperature inside the reformers 1 and 2 is directly controlled. You may measure.

Next, in the target oxidant flow rate correcting means 232, the target air to the reformer calculated by the target value calculating means 13 for calculating the target value in accordance with the load electric energy required for the fuel cell system. Correction and addition are performed using the flow rate Q0 and the air flow rate ΔQ required for the reformer temperature control calculated by the temperature feedback control means 231 described above.

Further, the reformer inlet air flow rate detecting device 28
Of the anode pressure regulating valve 7 of the fuel cell 3 by the flow rate feedback means 233 so that the output q of the fuel cell 3 becomes the target flow rate Q0 + ΔQ required by the reformer calculated by the target oxidant flow rate correction means 232 described above. Is calculated and controlled.

Further, other control contents in the reformer temperature control means 23 will be described with reference to FIG. In the reformer temperature control means 23, first, in the pressure comparison means 234, the anode of the fuel cell 3 calculated by the target value calculation means 13 for calculating the target value according to the load electric energy required for the fuel cell system. The target pressure P0 on the anode side is compared with the output p of the pressure detector 20 on the anode side.

At this time, the anode side pressure detecting device 20
If the actual pressure p deviates from the upper and lower limits of the target pressure, the next pressure feedback control means 235 calculates a corrected air flow rate for the air supply device 4. In addition,
When it is not determined that the pressure detection device 20 on the anode side is lower or higher than the target pressure, the process proceeds to the next step without calculating the correction air flow rate by the pressure feedback control unit 235.

Next, in the target oxidant flow rate correcting means 236, the target value for the air supply device 4 calculated by the target value calculating means 13 for calculating the target value in accordance with the load electric energy required for the fuel cell system. The total air flow Q0 and the corrected air flow ΔQ calculated by the pressure feedback control means 235 are corrected and added, and the air flow of the air supply device 4 is controlled based on the result.

Next, the operation of the cathode side pressure control means (the target pressure calculation means 24 and the cathode pressure control means 25 in FIG. 4) according to the present invention will be described.

From the output of the anode-side inlet pressure detector 20 of the fuel cell body 3, the target value of the cathode-side inlet pressure of the fuel cell body 3 is increased by a predetermined value set in advance. Anode side inlet pressure detector 20
The target value of the cathode-side inlet pressure of the fuel cell body 3 is calculated by adding the predetermined value to the output of the fuel cell main body 3.

Then, the cathode-side pressure regulating valve 6 is controlled so that the pressure measured by the cathode-side inlet pressure detector 20 of the fuel cell body 3 becomes the target value calculated by the target pressure calculating means 24 as described above. Adjust the opening of.

The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a fuel cell system of the present invention.

FIG. 2 is a block diagram for explaining control contents of a reformer temperature control means according to the present invention.

FIG. 3 is a block diagram for explaining another control content of the reformer temperature control means according to the present invention.

FIG. 4 is a block diagram showing a specific example of the fuel cell system of the present invention.

[Explanation of symbols]

 1, 2 ... reformer 3 ... fuel cell body 4 ... oxidant supply means 6 ... cathode side pressure adjustment valve 7 ... anode side pressure adjustment valve 9 ... reformer temperature detection means 20 ... anode side inlet pressure detection means 22 ... cathode side inlet pressure detecting means 23 ... reformer temperature control means 24, 25 ... cathode side pressure controlling means

Claims (5)

[Claims] 1. An oxidant supply unit for supplying an oxidant to a fuel cell system, a first oxidant supply system for supplying an oxidant supplied from the oxidant supply unit to a reformer, and the oxidant. A second oxidant supply system for supplying the oxidant supplied from the supply means to the cathode side of the fuel cell body, a raw material gas supply means for supplying a raw material gas obtained by evaporating raw fuel to the reformer, The raw material gas supplied from the raw material gas supply means was subjected to a reforming reaction in a catalyst layer provided therein to generate a hydrogen-containing reformed gas, and the oxidant supplied from the oxidant supply means was provided inside. A reformer that performs a partial oxidation reaction in the catalyst layer to obtain a calorie necessary for the reforming reaction, the reformed gas is supplied to an anode side, and an oxidant from the oxidant supply unit is supplied to a cathode side. A fuel cell body for generating electricity, and the fuel cell An anode-side pressure regulating valve provided in an exhaust reforming gas system at an anode-side outlet of the main body and adjusting an anode-side pressure; and a cathode-side exhaust gas oxidizing system provided at a cathode-side outlet of the fuel cell main body. In a fuel cell system having a cathode-side pressure adjusting valve for adjusting pressure, a reformer temperature detecting means for detecting a temperature of the reformer, and a reformer detected by the reformer temperature detecting means A reformer temperature control means for controlling an opening of an anode-side pressure regulating valve of the fuel cell main body such that an actual temperature of the fuel cell main body reaches a target temperature; and detecting a pressure at an anode-side inlet of the fuel cell main body. Pressure detecting means, pressure detecting means for detecting the pressure at the cathode side inlet of the fuel cell main body, and a cathode of the fuel cell main body based on the actual pressure detected by these two pressure detecting means. Fuel cell system, characterized in that it further comprises a cathode-side pressure control means for controlling the pressure of the de-side inlet, the. 2. The cathode-side pressure control means, wherein the target value of the pressure at the cathode-side inlet is higher than the output of the anode-side inlet pressure detector by a predetermined value. A target value calculating means for calculating a target value of the pressure at the cathode side inlet by adding a predetermined value to the output value of the target, wherein the actual pressure detected by the cathode side inlet pressure detecting means is the target value 2. The fuel cell system according to claim 1, wherein an opening degree of the cathode-side pressure adjusting valve is controlled so as to reach a target value calculated by the calculating means. 3. The anode-side target pressure calculating means for calculating a target value of the anode-side inlet pressure based on the required value of the load power of the fuel cell body, the reformer temperature control means; Target oxidant flow rate calculation means for calculating a target value of the total oxidant flow rate to be supplied by the oxidant supply means based on the value, a target value of the anode side inlet pressure and an output value of the anode side inlet pressure detection means When the output value of the anode-side inlet pressure detecting means deviates from the upper limit or the lower limit of the target value of the anode-side inlet pressure, the anode-side inlet pressure detecting means A pressure feedback control unit that calculates a correction value of the oxidant flow rate such that the detected actual pressure becomes a target value of the anode-side inlet pressure; The fuel cell system according to claim 1 or 2, wherein comprising: the target oxidant flow rate correction means for correcting the target value of the total oxidant flow rate based on the correction value of the oxidizing agent flow rate, a. 4. The reformer target temperature calculating means for calculating a target temperature of the reformer based on a required value of load power of the fuel cell main body, and the fuel cell main body. A reformer target oxidant flow rate calculating means for calculating a target value of the oxidant flow rate to be supplied to the reformer based on the required value of the load power of the reformer; Correction means for correcting the calculated target oxidant flow rate such that the actual temperature detected by the reformer temperature detection means becomes the target temperature with respect to the target oxidant flow rate. The fuel cell system according to claim 1, wherein: 5. The pressure difference between the inlet side pressure of the reformer and the outlet side pressure of the reformer is adjusted by adjusting the difference between the pressure on the cathode side of the fuel cell and the pressure on the anode side of the fuel cell. And
A method for controlling a temperature of a reformer, comprising controlling a temperature of the reformer by adjusting a flow rate of an oxidant flowing into the reformer.