JP6942017B2 - Fuel cell device - Google Patents

Description

The present disclosure relates to a fuel cell device.

Development of various power generation systems equipped with fuel cells such as solid oxide fuel cells (SOFCs) is underway.

The fuel cell system disclosed in Patent Document 1 includes a plurality of fuel cell stacks, and controls a DC / DC converter connected to each stack to enable continuous use of the deteriorated stack.

Japanese Unexamined Patent Publication No. 2014-026862

In such a fuel cell system, control with good power generation efficiency when one common auxiliary equipment group acts on two stacks has not been considered.

An object of the present disclosure is to provide a fuel cell device capable of improving power generation efficiency even when one common auxiliary equipment group acts on two stacks.

The fuel cell apparatus according to one embodiment includes a first stack and a second stack, each containing one or more fuel cell cells. The fuel cell device includes a first auxiliary machine group that acts in common with the first stack and the second stack. The fuel cell device includes a first converter and a second converter in which output currents from the first stack and the second stack are input and a predetermined output voltage is output, respectively. The fuel cell device includes a control unit that controls the duty ratio of the first converter and the second converter. The control unit controls so that the difference between the first target value of the output current from the first stack and the second target value of the output current from the second stack is equal to or less than the first predetermined value . When the difference between each target value and the measured value of the output current from the corresponding stack exceeds the second predetermined value, it is determined to be abnormal .

According to the fuel cell device according to the embodiment, the power generation efficiency can be improved even when one common auxiliary machine group acts on the two stacks.

It is a functional block diagram which shows schematic structure of the power generation system including the fuel cell apparatus which concerns on one Embodiment. It is a functional block diagram which shows schematic structure of the fuel cell apparatus which concerns on one Embodiment. It is a flowchart which shows the operation of the fuel cell apparatus which concerns on one Embodiment.

Hereinafter, one embodiment of the present disclosure will be described with reference to the accompanying drawings. In the attached drawings, the line through which electric power flows is indicated by a solid line, the line through which control signals or various information are transmitted is indicated by a broken line, and the line through which heat, water, gas, air, etc. flows is indicated by a chain line. First, the configuration of the power generation system S including the fuel cell device 1 according to the embodiment of the present disclosure will be described.

FIG. 1 is a functional block diagram schematically showing a configuration of a power generation system S including a fuel cell device 1 according to an embodiment.

As shown in FIG. 1, the power generation system S is connected to a hot water storage tank T, a load L, and a commercial power supply (grid) G. As shown in FIG. 1, the power generation system S generates power based on gas (city gas, propane gas, etc., hereinafter referred to as gas), water, and air supplied from the outside. The power generation system S supplies the generated power to the load L and the like. In particular, the power generation system S controls the output as AC power to supply the AC power to the load L and the like.

The power generation system S includes a fuel cell device 1, an inverter 2, an exhaust heat recovery processing unit 3, and a circulating water treatment unit 4.

The inverter 2 is connected to the fuel cell device 1. The inverter 2 converts the DC power generated by the fuel cell device 1 into AC power. The AC power output from the inverter 2 is supplied to the load L via the distribution board or the like. The load L receives the AC power output from the inverter 2 via the distribution board or the like. In FIG. 1, the load L is shown as one block, but is not limited thereto. The load L may be composed of an arbitrary number of various electric devices. The load L can also receive power from the commercial power source G via a distribution board or the like.

The exhaust heat recovery processing unit 3 recovers exhaust heat from the exhaust generated by the power generation of the fuel cell device 1. The exhaust heat recovery processing unit 3 may be configured by, for example, a heat exchanger or the like. The waste heat recovery processing unit 3 is connected to the circulating water treatment unit 4 and the hot water storage tank T.

The circulating water treatment unit 4 circulates water from the hot water storage tank T to the waste heat recovery treatment unit 3. The water supplied to the waste heat recovery processing unit 3 is heated by the heat recovered by the waste heat recovery processing unit 3 and returns to the hot water storage tank T. The exhaust heat recovery processing unit 3 discharges the exhaust that has recovered the exhaust heat to the outside. The heat recovered by the waste heat recovery processing unit 3 can be used for heating gas, water, air, etc. supplied from the outside.

The hot water storage tank T is connected to the waste heat recovery processing unit 3 and the circulating water treatment unit 4. The hot water storage tank T can store hot water generated by utilizing the exhaust heat recovered from the fuel cell device 1.

FIG. 2 is a functional block diagram schematically showing the configuration of the fuel cell device 1 according to the embodiment. FIG. 2 shows the fuel cell device 1 in the power generation system S shown in FIG. 1, and omits other functional parts. Hereinafter, the configuration of the fuel cell device 1 will be described in detail.

The fuel cell device 1 includes a control unit 10, a storage unit 20, a first auxiliary machine group 30a, a second auxiliary machine group 30b, a power generation unit 40, and a converter unit 50.

The fuel cell device 1 includes at least one processor as a control unit 10 in order to provide control and processing power for performing various functions, as described in more detail below. According to various embodiments, at least one processor may be configured as a single integrated circuit (IC) or at least one of a plurality of communicably connected ICs and discrete circuits. good. At least one processor may be configured according to various known techniques.

In one embodiment, the processor may include one or more circuits or units configured to perform one or more data computation procedures or processes. For example, the control unit 10 may include one or more processors, controllers, microprocessors, microcontrollers, application specific integrated circuits (ASICs), digital signal processing devices, programmable logic devices, field programmable gate arrays, or any of these devices or configurations. May include a combination of. The control unit 10 may include any combination of other known devices or configurations. With the above configuration, the control unit 10 may execute a function described later.

The control unit 10 is communicatively connected to the storage unit 20, the first auxiliary machine group 30a, the second auxiliary machine group 30b, the power generation unit 40, and the converter unit 50. The control unit 10 controls and manages the entire fuel cell device 1 including each of these functional units. The control unit 10 acquires a program stored in the storage unit 20 and executes the program. As a result, the control unit 10 realizes various functions related to each unit of the fuel cell device 1. When a control signal or various information is transmitted from the control unit 10 to another function unit, the control unit 10 and the other function unit may be connected by wire or wireless communication. The characteristic control of the fuel cell device 1 according to the embodiment, which is performed by the control unit 10, will be further described later. In one embodiment, the control unit 10 may measure a predetermined time, such as measuring the operating time (for example, power generation time) of the power generation unit 40 included in the fuel cell device 1.

The storage unit 20 is composed of, for example, a semiconductor memory, a magnetic disk, or the like. The storage unit 20 is not limited to these, and may be configured by any storage device. For example, the storage unit 20 may be configured by an optical storage device such as an optical disc, or may be configured by a magneto-optical disk or the like. The storage unit 20 stores the information acquired from the control unit 10. The storage unit 20 stores a program or the like executed by the control unit 10. In addition, the storage unit 20 also stores various data such as calculation results by the control unit 10. The storage unit 20 may also include a work memory or the like when the control unit 10 operates.

The fuel cell device 1 has, for example, two first auxiliary machine groups 30a and a second auxiliary machine group 30b. Hereinafter, when the first auxiliary machine group 30a and the second auxiliary machine group 30b are not particularly distinguished, they are simply collectively referred to as the auxiliary machine group 30. Gas, water, and air supplied from the outside flow into the first auxiliary machine group 30a and the second auxiliary machine group 30b in a state of being branched into two paths from one supply source. The auxiliary machine group 30 adjusts the flow rate of the inflowing gas, water, and air. The auxiliary machine group 30 includes piping portions such as gas pipes, reformed water pipes, air pipes and reformed gas branch pipes, as well as a gas flow meter and an air flow meter.

The first auxiliary machine group 30a includes, for example, a gas pump 31a, a reforming water pump 32a, an air blower 33a, a first reformer 34a, and a first branch pipe 35a. Similarly, the second auxiliary machine group 30b includes a gas pump 31b, a reformed water pump 32b, an air blower 33b, a second reformer 34b, and a second branch pipe 35b as an example. When the components included in each of the first auxiliary machine group 30a and the second auxiliary machine group 30b are not particularly distinguished, it is simply like a gas pump 31, a reforming water pump 32, an air blower 33, a reformer 34, and a branch pipe 35. Collectively referred to as.

The gas pump 31 is arranged in the gas line inside the fuel cell device 1, for example, in front of the reformer 34. The gas pump 31 supplies gas to the reformer 34. Any gas pump 31 can be adopted as long as it can deliver gas to the reformer 34. At this time, the gas pump 31 may control the amount of gas supplied to the reformer 34 based on the control signal from the control unit 10. In this way, the gas pump 31 supplies the gas used for the electrochemical reaction when the power generation unit 40 generates power. In the fuel cell device 1, the gas may be desulfurized or the gas may be preheated in the front stage of the gas pump 31 in the internal gas line. The fuel cell device 1 may use the exhaust heat recovered by the exhaust heat recovery processing unit 3 as a heat source for heating the gas. The gas is, for example, city gas, LPG, and the like, but is not limited thereto. For example, the gas may be natural gas, coal gas, or the like, depending on the fuel cell.

The reformed water pump 32 is arranged in the reformed water line inside the fuel cell device 1, for example, in front of the reformer 34. The reformed water pump 32 supplies steam to the reformer 34. As the reforming water pump 32, any one can be adopted as long as it can deliver steam to the reformer 34. At this time, the reforming water pump 32 may control the amount of steam supplied to the reformer 34 based on the control signal from the control unit 10. The fuel cell device 1 generates steam in the internal reforming water line in front of the reforming water pump 32 based on water from the outside. The fuel cell device 1 may generate water vapor from water recovered from the exhaust gas of the power generation unit 40 as a raw material. The fuel cell device 1 may use the exhaust heat recovered by the exhaust heat recovery processing unit 3 as a heat source for generating water vapor.

The air blower 33 is arranged in the air line inside the fuel cell device 1 in front of, for example, the power generation unit 40. The air blower 33 supplies air to the power generation unit 40. Any air blower 33 can be used as long as it can send air to the power generation unit 40. At this time, the air blower 33 may control the amount of air supplied to the power generation unit 40 based on the control signal from the control unit 10. In this way, the air blower 33 supplies the air used for the electrochemical reaction when the power generation unit 40 generates electricity. The fuel cell device 1 preheats the air taken in from the outside in the front stage of the air blower 33 in the internal air line. The fuel cell device 1 may use the exhaust heat recovered by the exhaust heat recovery processing unit 3 as a heat source for heating the air.

The reformer 34 uses the gas supplied from the gas pump 31 and the steam supplied from the reformed water pump 32 to generate a reformed gas containing hydrogen. The reformer 34 supplies the generated reforming gas to the power generation unit 40 via the branch pipe 35.

The power generation unit 40 has four first stacks 41a, a second stack 41b, a third stack 41c, and a fourth stack 41d. As an example, the four first stack 41a, the second stack 41b, the third stack 41c, and the fourth stack 41d are stored in a common storage unit. The first reformer 34a is connected to the gas pump 31a and the reforming water pump 32a on the inflow side, and is connected to the first stack 41a and the second stack 41b on the supply side. Similarly, the second reformer 34b is connected to the gas pump 31b and the reforming water pump 32b on the inflow side, and is connected to the third stack 41c and the fourth stack 41d on the supply side. Hereinafter, when the first stack 41a, the second stack 41b, the third stack 41c, and the fourth stack 41d are not particularly distinguished, they are simply collectively referred to as the stack 41.

The stack 41 generates electricity by reacting the reformed gas generated by the reformer 34 with oxygen contained in the air supplied from the air blower 33 and filling the inside of the power generation unit 40. That is, the fuel cell stack 41 generates electricity by an electrochemical reaction. Along with the electrochemical reaction, the stack 41 generates heat in the power generation unit 40. The reformer 34 has been described as being a reformer that performs steam reforming, but the present invention is not limited thereto. The reformer 34 may be a reformer or the like that performs partial oxidative reforming (Partial Oxidation (POX)) that generates hydrogen using air or the like containing oxygen.

More specifically, in the first reformer 34a, gas and steam flow in from the gas pump 31a and the reforming water pump 32a, respectively. The first reformer 34a supplies the reforming gas to the first stack 41a and the second stack 41b by branching the reforming gas into two lines by the first branch pipe 35a. In other words, the first branch pipe 35a is connected to the first reformer 34a and supplies the reforming gas to the first stack 41a and the second stack 41b. In this way, the gas from the gas pump 31a is reformed in the first reformer 34a and then commonly supplied to the first stack 41a and the second stack 41b. Similarly, the gas from the gas pump 31b is reformed in the second reformer 34b and then commonly supplied to the third stack 41c and the fourth stack 41d via the second branch pipe 35b. On the other hand, the air from the air blower 33 fills the entire power generation unit 40 including the first stack 41a, the second stack 41b, the third stack 41c, and the fourth stack 41d.

As described above, the first auxiliary machine group 30a acts in common with the first stack 41a and the second stack 41b. Similarly, the second auxiliary machine group 30b acts in common with the third stack 41c and the fourth stack 41d. As a result, the fuel cell device 1 can contribute to cost reduction because the number of devices is reduced as compared with the case where one auxiliary machine group operates on one stack. Since the number of auxiliary equipment groups to be controlled and managed by the fuel cell device 1 is reduced, it can also contribute to the reduction of the processing load in the control unit 10. Therefore, since the control unit 10 has a sufficient processing capacity for the processing load generated in the normal control, even if some emergency event occurs, the control unit 10 allocates the processing to an arbitrary functional unit and appropriately responds to it. Is possible. By branching the reformed gas by the branch pipe 35, the fuel cell device 1 can easily bring the flow rates of the reformed gas in the corresponding two stacks 41 close to each other. Therefore, the fuel cell device 1 can easily bring the measured values of the output currents from the two corresponding stacks 41 closer to each other in the control described later.

The stack 41 is composed of SOFC (Solid Oxide Fuel Cell) as an example. However, the stack 41 is not limited to this, and the stack 41 is, for example, a polymer electrolyte fuel cell (PEFC), a phosphoric acid fuel cell (PAFC), or a molten carbonate fuel cell. It may be composed of a fuel cell such as (Molten Carbonate Fuel Cell (MCFC)). The stack 41 includes one or more fuel cell cells. The fuel cell device 1 has, for example, four stacks 41 capable of generating about 700 W by itself. In this case, the power generation unit 40 can output about 3 kW of electric power as a whole. However, the present invention is not limited to this, and the fuel cell device 1 may have an arbitrary number of stacks 41 capable of generating arbitrary electric power according to the output electric power from the desired power generation unit 40. The stack 41 outputs the generated DC power to the converter unit 50.

The converter unit 50 includes four current sensors 51a, 51b, 51c and 51d, and four first converter 52a, second converter 52b, third converter 52c and fourth converter 52d. Hereinafter, when the four current sensors 51a, 51b, 51c and 51d are not particularly distinguished, they are simply collectively referred to as the current sensor 51. Similarly, hereinafter, when the first converter 52a, the second converter 52b, the third converter 52c and the fourth converter 52d are not particularly distinguished, they are simply collectively referred to as the converter 52.

The current sensor 51a is arranged between the first stack 41a and the first converter 52a. The current sensor 51a measures the direct current output from the first stack 41a. The current sensor 51a may be composed of any element as long as the output current from the first stack 41a can be appropriately measured. Similar configurations and functions apply to current sensors 51b, 51c and 51d. The measured value of the output current from the stack 41 measured by the current sensor 51 is output to the control unit 10. The control unit 10 stores the data related to the actually measured value in the storage unit 20 as needed.

The first converter 52a is electrically connected to the first stack 41a and receives the DC power output from the first stack 41a. The first converter 52a supplies the DC power output from the first stack 41a to the inverter 2 in a state of converting the voltage. That is, the first converter 52a may be a DC / DC converter as an example. In the following, in particular, the first converter 52a will be described as being a boost converter. In this way, the first converter 52a receives the output current from the first stack 41a and outputs a predetermined output voltage (intermediate link voltage). The output voltage from the first converter 52a is controlled by the control unit 10 by using an arbitrary method such as a pulse width modulation method (Pulse Width Modulation (PWM)) or a variable frequency modulation method (VFM). NS. Similar configurations and functions apply to the second converter 52b, the third converter 52c and the fourth converter 52d.

Hereinafter, the operation of the fuel cell device 1 according to the embodiment will be described. In particular, the control of the first converter 52a and the second converter 52b performed by the control unit 10 will be mainly described. It should be understood that the following description is similarly applied to the control of the third converter 52c and the fourth converter 52d.

The control unit 10 controls the first converter 52a and the second converter 52b so that the measured value of the output current from the first stack 41a approaches the measured value of the output current from the second stack 41b. More specifically, the control unit 10 acquires the target value and the measured value of the output currents of the first stack 41a and the second stack 41b, respectively, and outputs the corresponding converter 52 so that the measured value approaches the target value. Control the voltage. For example, the control unit 10 controls the duty ratios of the first converter 52a and the second converter 52b.

More specifically, in the control unit 10, the difference between the first target value of the output current from the first stack 41a and the second target value of the output current from the second stack 41b is equal to or less than the first predetermined value. To control. The first predetermined value means, for example, a range of target values determined so that the measured value of the output current from the first stack 41a approaches the measured value of the output current from the second stack 41b. The control unit 10 controls the first converter 52a and the second converter 52b so that the measured values of the output currents from the first stack 41a and the second stack 41b approach the first target value and the second target value, respectively. For example, the control unit 10 controls the first converter 52a and the second converter 52b so that the measured value of the output current from the first stack 41a and the measured value of the output current from the second stack 41b are substantially the same. do.

The target value of the output current may be, for example, predetermined by the installer of the fuel cell device 1, may be appropriately determined by the user, or may be appropriately determined by any other method at any other timing. good. The target value of the output current may be set to substantially the same value between the first stack 41a and the second stack 41b. The control unit 10 stores the acquired data regarding the target value of the output current in the storage unit 20 as needed.

As described above, the control unit 10 acquires the measured value of the output current measured by the current sensor 51. The control unit 10 may periodically acquire the measured value of the output current at a preset constant cycle, or may acquire the measured value of the output current at any other timing.

The control unit 10 determines whether or not the target value and the measured value of the output currents of the first stack 41a and the second stack 41b are substantially the same as each other. When the target value and the measured value are different, the control unit 10 controls the output voltage of the corresponding converter 52.

More specifically, when the measured value is smaller than the target value, the control unit 10 increases the output current from the corresponding stack 41 by lowering the output voltage from the corresponding converter 52. For example, the control unit 10 causes the PWM method, the ratio of the pulse width _{t P} with respect to the pulse period _{T P (t P / T P} ), namely by reducing the Deyuti ratio, reducing the output voltage from the corresponding converter 52 ..

On the other hand, when the measured value is larger than the target value, the control unit 10 increases the output voltage from the corresponding converter 52 to reduce the output current from the corresponding stack 41. For example, in the PWM method, the control unit 10 increases the output voltage from the corresponding converter 52 by increasing _{t P} / T _P.

When the difference between the target value and the actually measured value exceeds the second predetermined value, the control unit 10 may determine that it is abnormal. The second predetermined value means, for example, a value within a range in which the amount of gas for power generation supplied to the stack 41 and the value of the output current from the stack 41 appropriately correspond to each other. That is, if the measured value is very small compared to the target value, a large amount of surplus gas not used for power generation may be generated in the stack 41. As a result, the stack 41 may be deteriorated due to heat generated by the excess gas. On the contrary, when the measured value is much larger than the target value, there is a possibility that the stack 41 will run out of gas for power generation. As a result, the power generation in the stack 41 may be stopped. The second predetermined value means the difference between the target value and the actually measured value so that such a situation does not occur. For example, the second predetermined value is larger than the first predetermined value. As an example, when the difference between the target value and the actually measured value exceeds a certain threshold value, the control unit 10 may determine that it is abnormal.

When the control unit 10 determines that the difference between the target value and the actually measured value exceeds the second predetermined value and is abnormal, the stack 41 is performed by a visual method, an auditory method, an arbitrary method including a combination thereof, or the like. The output status of may be notified.

The control unit 10 may control the operation of the auxiliary equipment group 30 based on the target value of the output current from the stack 41. For example, the control unit 10 may control the first auxiliary machine group 30a based on the first target value and the second target value of the common output currents of the first stack 41a and the second stack 41b. More specifically, the control unit 10 is a first auxiliary machine so that the measured values of the output currents from the first stack 41a and the second stack 41b are close to the common first target value and second target value to some extent. Group 30a may be controlled to adjust the flow rates of gas, water, and air flowing in from the outside. For example, the control unit 10 may similarly control the second auxiliary machine group 30b based on the third target value and the fourth target value of the common output currents of the third stack 41c and the fourth stack 41d.

FIG. 3 is a flowchart showing the operation of the fuel cell device 1 according to the embodiment.

The control unit 10 acquires a target value of the output current from the stack 41 (step S101). At this time, the control unit 10 sets the difference between the first target value of the output current from the first stack 41a and the second target value of the output current from the second stack 41b to be equal to or less than the first predetermined value. Control.

The control unit 10 acquires the measured value of the output current from the stack 41 by the current sensor 51 (step S102).

The control unit 10 determines whether or not the acquired target value of the output current and the actually measured value are substantially the same as each other (step S103). When the control unit 10 determines that they are substantially the same, the control unit 10 ends the flow. If the control unit 10 determines that they are not substantially the same, the control unit 10 proceeds to step S104.

In step S104 and subsequent steps, the control unit 10 controls the converter 52 so that the measured value of the output current from the stack 41 approaches the target value.

When the control unit 10 determines that the target value and the actually measured value are not substantially the same as each other, the control unit 10 determines whether or not the difference between them exceeds the second predetermined value (step S104). If the control unit 10 determines that the value has been exceeded, the control unit 10 proceeds to step S105. If the control unit 10 determines that the value is not exceeded, the control unit 10 proceeds to step S106.

When the control unit 10 determines that the difference between the target value and the actually measured value exceeds the second predetermined value, it determines that it is abnormal and notifies the output state of the stack 41 by an arbitrary method (step S105).

When the control unit 10 determines that the difference between the target value and the actually measured value does not exceed the second predetermined value, the control unit 10 determines whether or not the actually measured value is smaller than the target value (step S106). When the control unit 10 determines that the measured value is smaller than the target value, the control unit 10 proceeds to step S107. When the control unit 10 determines that the measured value is larger than the target value, the control unit 10 proceeds to step S108.

When the control unit 10 determines that the measured value is smaller than the target value, the control unit 10 reduces the output voltage from the corresponding converter 52 to increase the output current from the corresponding stack 41 (step S107). After that, the control unit 10 returns to step S102 again.

When the control unit 10 determines that the measured value is larger than the target value, the control unit 10 increases the output voltage from the corresponding converter 52 to reduce the output current from the corresponding stack 41 (step S108). After that, the control unit 10 returns to step S102 again.

The fuel cell device 1 according to the above embodiment controls the first converter 52a and the second converter 52b so that the output current values of the first stack 41a and the second stack 41b are substantially the same. Since the output current values of the fuel cell device 1 are substantially the same, the operation of the first stack 41a and the second stack 41b can be stabilized even if the auxiliary equipment group 30 is shared. For example, when 10A is set as the target value of the output current from the stack 41, the fuel cell device 1 outputs the current of the first stack 41a to 8A and outputs the current of the second stack 41b to 12A. Think about it. In this case, in the first stack 41a, a large amount of surplus gas not used for power generation may be generated. As a result, the first stack 41a may be deteriorated due to heat generated by the excess gas. On the contrary, with respect to the second stack 41b, there is a possibility that the gas for power generation will be insufficient in the second stack 41b. As a result, the power generation in the second stack 41b may be stopped. The fuel cell device 1 according to the embodiment can avoid such a situation by making the values of the output currents from the two stacks 41 substantially the same. That is, the fuel cell device 1 can supply an appropriate amount of gas to each stack 41 according to the value of the output current from the two stacks 41, and the gas can be efficiently used for power generation. As described above, according to the fuel cell device 1 according to the embodiment, the power generation efficiency can be improved. The fuel cell device 1 can improve the power generation efficiency as described above while contributing to the reduction of the manufacturing cost by using the first auxiliary machine group 30a in common between the first stack 41a and the second stack 41b.

The fuel cell device 1 acquires the target value and the measured value of the output current from the stack 41, and controls the output voltage of the corresponding converter 52 so that the measured value approaches the target value, thereby performing more accurate control. Is possible. That is, the fuel cell device 1 can more accurately match the values of the output currents from the two stacks 41 to be substantially the same. As a result, the fuel cell device 1 can suppress the deterioration of the stack 41 and continue stable operation. The fuel cell device 1 enables optimum power generation according to the usage environment by appropriately setting a target value. As a result, the fuel cell device 1 can be operated stably for a longer period of time, and the reliability as a product can be improved.

The fuel cell device 1 can notify the user and the like of the output state of the stack 41 by determining that it is abnormal when the difference between the target value and the actually measured value exceeds the second predetermined value. In other words, the fuel cell device 1 can make the user recognize the abnormality of the output state of the stack 41.

By controlling the operation of the auxiliary equipment group 30 in addition to the control of the converter unit 50, the fuel cell device 1 can more accurately match the values of the output currents from the two stacks 41 to be substantially the same. For example, the fuel cell device 1 can adjust the flow rate of the gas in the stack 41 by controlling the auxiliary equipment group 30, and roughly adjust the measured value of the output current to the target value. The fuel cell device 1 can accurately adjust the measured value of the output current from the stack 41 to the target value by controlling the converter unit 50. As described above, the fuel cell device 1 can roughly adjust the output current from the stack 41 by, for example, the auxiliary equipment group 30, and make a more accurate adjustment by the converter unit 50.

In the fuel cell device 1, since the auxiliary machine group 30 includes the gas pump 31, the reforming water pump 32, and the air blower 33, the flow rate of the gas, water, and air flowing in from the outside can be easily adjusted. .. As a result, the fuel cell device 1 can supply an appropriate amount of gas to the stack 41. Therefore, the fuel cell device 1 can improve the power generation efficiency.

The fuel cell device 1 has two sets of one auxiliary machine group 30 and two stacks 41, so that a large amount of electric power can be supplied while maintaining the power generation efficiency. That is, the fuel cell device 1 generates electricity while suppressing deterioration of each stack 41 and continuing stable operation by matching the output current values between the two paired stacks 41 to be substantially the same. The amount can be improved.

The fuel cell device 1 stores the four first stacks 41a, the second stack 41b, the third stack 41c, and the fourth stack 41d in a common storage unit, so that the temperature required for power generation in each stack 41 can be appropriately set. Can be maintained. Thereby, the fuel cell device 1 can improve the reliability as a product.

Although the present disclosure has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications or modifications based on the present disclosure. It should be noted, therefore, that these modifications or modifications are within the scope of this disclosure. For example, the functions included in each means or each step can be rearranged so as not to be logically inconsistent, and a plurality of means or steps can be combined or divided into one. be.

For example, the power generation unit 40 and the stack 41 according to the embodiment are not limited to the above-described configurations, and various configurations can be adopted. The fuel cell device 1 may have at least two stacks 41 that generate electricity using gas. The stack 41 may be composed of a single fuel cell.

1 Fuel cell device 2 Inverter 3 Exhaust heat recovery processing unit 4 Circulating water treatment unit 10 Control unit 20 Storage unit 30 Auxiliary equipment group 30a First auxiliary equipment group 30b Second auxiliary equipment group 31, 31a, 31b Gas pumps 32, 32a, 32b Rectifier water pumps 33, 33a, 33b Air blower 34 Rectifier 34a First rectifier 34b Second rectifier 35a First branch pipe 35b Second branch pipe 40 Power generation unit 41 Stack 41a First stack 41b Second stack 41c 3rd stack 41d 4th stack 50 Converter section 51, 51a, 51b, 51c, 51d Current sensor 52 Converter 52a 1st converter 52b 2nd converter 52c 3rd converter 52d 4th converter G Commercial power supply L Load S Power generation system T Hot water storage tank

Claims (8)

A first stack and a second stack, each containing one or more fuel cell cells,
The first auxiliary machine group that acts in common with the first stack and the second stack,
The first converter and the second converter, which are input with the output currents from the first stack and the second stack and output a predetermined output voltage, respectively,
A control unit that controls the duty ratios of the first converter and the second converter,
With
The control unit
The difference between the first target value of the output current from the first stack and the second target value of the output current from the second stack is controlled to be equal to or less than the first predetermined value.
When the difference between each target value and the measured value of the output current from the corresponding stack exceeds the second predetermined value, it is determined to be abnormal.
Fuel cell device. The control unit sets the first converter and the second converter so that the measured values of the output currents from the first stack and the second stack approach the first target value and the second target value, respectively. Control,
The fuel cell device according to claim 1. The control unit controls the first converter and the second converter so that the measured values of the output currents from the first stack and the second stack are substantially the same.
The fuel cell device according to claim 2. The control unit controls the operation of the first auxiliary machine group based on the first target value and the second target value.
The fuel cell device according to any one of claims 1 to 3. The first auxiliary equipment group includes a gas pump, a reforming water pump and an air blower that adjust the flow rates of gas, water and air flowing in from the outside, and a first reformer that generates reforming gas. A first branch pipe connected to the first reformer and supplying reforming gas to the first stack and the second stack.
The fuel cell device according to any one of claims 1 to 4. A third stack and a fourth stack, each containing one or more fuel cell cells,
A second auxiliary machine group that acts in common with the third stack and the fourth stack,
A third converter and a fourth converter in which output currents from the third stack and the fourth stack are input and a predetermined output voltage is output, respectively.
With more
The control unit
The difference between the third target value of the output current from the third stack and the fourth target value of the output current from the fourth stack is controlled to be equal to or less than the first predetermined value.
The fuel cell device according to any one of claims 1 to 5. The control unit sets the third converter and the fourth converter so that the measured values of the output currents from the third stack and the fourth stack approach the third target value and the fourth target value, respectively. Control,
The fuel cell device according to claim 6. The second auxiliary equipment group includes a gas pump, a reforming water pump, and an air blower that adjust the flow rates of gas, water, and air flowing in from the outside, a second reformer that generates reforming gas, and a second reformer. A second branch pipe connected to the second reformer and supplying reforming gas to the third stack and the fourth stack.
The fuel cell device according to claim 6 or 7.

Images