JP2013176213A - Fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell system capable of reducing a load on a battery and an auxiliary machine, while preventing a decrease in performance by regulating variation in electric power generation by a fuel cell, and capable of preventing deterioration in fuel economy of the vehicle.SOLUTION: A control part of a fuel cell system constituting a portion of a fuel cell system of a vehicle is configured to feedback road environments or the like to voltage control of a fuel cell. The control part determines whether or not it is an electric potential variation suppression mode of the fuel cell in accordance with the road environments affecting a travel state (step S34) after calculating a target voltage α of the fuel cell on the basis of an accelerator opening Wt of the vehicle (step S13). When the electric potential variation suppression mode is determined, the control part further determines the details of the road environments (step S35), and controls the fuel cell with a voltage value obtained by multiplying a regulation rate R corresponding to each of the road environments by the target voltage α.

Description

  The present invention relates to a fuel cell system, and more particularly to a technique for controlling a fuel cell voltage in a fuel cell system.

  In general, in the control of a vehicle using a fuel cell as a driving energy source, the torque (average required torque) that the driving motor should output is calculated in accordance with the accelerator operation of the user (driver, operator). Further, based on the average required torque, power to be supplied by the fuel cell system (system required power) is calculated, and power generation control of the fuel cell system is performed according to the system required power. At this time, voltage fluctuation occurs during power generation of the fuel cell due to fluctuations in system power demand accompanying the accelerator operation, and the output performance (characteristics) of the fuel cell tends to decrease.

  In order to suppress such a decrease in the output performance of the fuel cell, the present applicant limits the amount of change in the power generated by the fuel cell when the system required power fluctuates (limit of the output voltage). A fuel cell system is proposed in which power corresponding to the amount of change (limited voltage) in the generated power of a restricted fuel cell is supplemented by a secondary battery (battery) or the like (see, for example, Patent Document 1). ).

JP 2007-005038 A

  By the way, the voltage rise width (potential fluctuation width) and the voltage rise occurrence frequency (potential fluctuation occurrence frequency) of the fuel cell when the generated power fluctuation of the fuel cell as described above occurs are determined by the fuel cell system including the fuel cell. There is a tendency to vary depending on the situation in which the mounted vehicle travels and the road environment (collectively referred to as “running state”). For example, the voltage rise width and voltage rise occurrence frequency when traveling on a highway can be relatively greater than those when traveling in an urban area. Regardless of the difference in road environment and the like, when the output of the fuel cell is uniformly limited as in the conventional fuel cell system described above, the load on the battery and the auxiliary machine that supplements the limited power becomes very high. In addition, the fuel consumption of the vehicle may be deteriorated.

  Therefore, the present invention has been made in view of such circumstances, and it is possible to reduce the load on the battery and the auxiliary machine while limiting the fluctuation of the power generated by the fuel cell to prevent the performance from being reduced, and to reduce the fuel consumption of the vehicle. An object of the present invention is to provide a fuel cell system capable of suppressing deterioration.

  In order to solve the above-described problems, a fuel cell system according to the present invention includes a fuel cell and a control unit that controls an output voltage of the fuel cell, and the control unit is a fuel cell system according to the accelerator opening of the vehicle. The required power of the fuel cell is calculated based on the required system power, the target voltage and / or target potential fluctuation frequency of the fuel cell is set based on the required power, and the vehicle running state Based on the above, control is performed to change the target voltage and / or target potential fluctuation frequency so as to be limited within a predetermined range. “Accelerator opening” indicates the depression rate when 0% is not depressed and 100% when the accelerator is depressed to the maximum.

  In the fuel cell system configured as described above, the accelerator opening changes according to the accelerator operation of the user, and the system required power of the fuel cell system is calculated according to the accelerator opening by the control means. The control means also controls the system required power with the fuel cell in order to limit the fluctuation amount of the power generated by the fuel cell when the system required power of the fuel cell system fluctuates to prevent the fuel cell from degrading, for example, The power is allocated to the battery provided in the vehicle, and the required power of the fuel cell is calculated according to the ratio. Further, the control means sets the target voltage and / or target potential fluctuation frequency of the fuel cell for outputting the necessary power. In the present invention, the set target voltage and / or target potential fluctuation frequency is not limited to the predetermined range based on the running state of the vehicle.

  Therefore, according to the present invention, when the system required power of the fuel cell system fluctuates, the amount of fluctuation of the power generated by the fuel cell is limited, so that the performance degradation of the fuel cell can be effectively prevented. Further, the target voltage and / or target potential fluctuation frequency to be output by the fuel cell can be appropriately limited as necessary based on the traveling state of the vehicle and the traveling state of the vehicle depending on the road environment.

1 is a schematic configuration diagram (system configuration diagram) of a vehicle including a first embodiment of a fuel cell system of the present invention. It is a system control block diagram of a vehicle provided with a first embodiment of a fuel cell system of the present invention. In the first embodiment of the fuel cell system of the present invention, it is a flowchart showing an example of a procedure for adjusting and controlling the output of the fuel cell provided in the fuel cell system by the control means. It is a figure which shows typically the relationship between the throttle opening in a vehicle, and the total voltage of a fuel cell. It is a graph which shows an example of the limiting rate multiplied with the initial target voltage of a fuel cell set with respect to an accelerator opening. It is a schematic diagram which shows the relationship between the voltage rise width of a fuel cell by the driving | running | working state of a vehicle, and the voltage rise occurrence frequency. In 2nd Embodiment of the fuel cell system of this invention, it is a flowchart which shows an example of the procedure which carries out adjustment control of the output of the fuel cell with which a control means is equipped with a control means. In 3rd Embodiment of the fuel cell system of this invention, it is a flowchart which shows an example of the procedure which adjusts and controls the output of the fuel cell with which a control means is equipped with a control means. It is a graph which shows an example of the limiting rate multiplied with the initial target voltage of a fuel cell set with respect to the accelerator opening according to road environment.

  Hereinafter, embodiments of the present invention will be described in detail. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention only to the embodiments. The present invention can be variously modified without departing from the gist thereof.

(First embodiment)
FIG. 1 is a schematic configuration diagram (system configuration diagram) of a vehicle including a first preferred embodiment of the fuel cell system of the present invention, and FIG. 2 is a system control block diagram of the fuel shown in FIG. It is the schematic which shows the structure paying attention to the control signal and electric power flow of a battery system. The vehicle 100 includes a power supply system 20 and a load unit 30, and a control unit 50 (control means) that controls both the power supply system 20 and the load unit 30. The power supply system 20 supplies power as a power source of the vehicle 100, and the load unit 30 converts the supplied power into mechanical power for driving the vehicle 100.

  The power supply system 20 includes a fuel cell system 200, a secondary battery 26 (battery), a DC-DC converter 64, a voltmeter 69 and an ammeter 67 for measuring the output voltage and output current of the fuel cell system 200, and A remaining capacity monitor 28 for measuring the remaining amount of the secondary battery 26 is provided.

  The fuel cell system 200 includes a fuel cell (FC) having a solid polymer electrolyte cell stack formed by stacking a plurality of unit cells in series. This fuel cell has a structure in which a membrane electrode assembly (MEA) in which a polymer electrolyte membrane or the like is sandwiched between two electrodes (an anode and a cathode) is sandwiched by a separator for supplying fuel gas and oxidizing gas. A plurality of unit cells having In general, the anode electrode has a catalyst layer for an anode electrode provided on a porous support layer and causes an oxidation reaction of hydrogen, while the cathode electrode has a catalyst layer for the cathode electrode that is a porous support layer. An electromotive reaction (cell reaction) is caused in the entire fuel cell as a result of the oxygen reduction reaction.

  In addition, the fuel cell is provided with a system for supplying fuel gas to the anode electrode, a system for supplying oxidizing gas to the cathode electrode, and a system for supplying coolant (none of which is shown), and a control unit In accordance with the control signal from 50, the supply amount of the fuel gas and the supply amount of the oxidizing gas are controlled, whereby the desired electric power is output from the fuel cell system 200.

  Further, the secondary battery 26 is connected in parallel to the fuel cell system 200 with respect to the load unit 30, and accompanies acceleration or deceleration of a surplus power storage source, a regenerative energy storage source during regenerative braking, and a fuel cell vehicle. Functions as an energy buffer when the load fluctuates. As the secondary battery 26, for example, a secondary battery such as a nickel / cadmium storage battery, a nickel / hydrogen storage battery, or a lithium secondary battery can be preferably used.

  On the other hand, the load unit 30 includes an accelerator 37 and an accelerator sensor 35 that measures the opening degree of the accelerator 37 (accelerator opening degree Wt: depression amount), and also via a traction motor 31 and a gear mechanism 32. A connected wheel 34 and a drive circuit 36 electrically connected to the traction motor 31 are provided. The traction motor 31 is connected to the power supply system 20 via the drive circuit 36, and the power generated by the traction motor 31 is transmitted to the wheels 34 via the gear mechanism 32.

  The drive circuit 36 is a circuit for driving the traction motor 31 using the electric power supplied from the power supply system 20, and the circuit configuration is not particularly limited. For example, a PCU (power control having a boosting and voltage conversion function) Unit), a power element (switching element), an inverter, and the like. Specifically, the drive circuit 36 converts, for example, DC power sent from the power supply system 20 into three-phase AC power and supplies it to the traction motor 31. At that time, the magnitude of the supplied three-phase AC power is determined by the drive circuit 36 controlled by the control unit 50 based on the input from the accelerator sensor 35 (accelerator opening Wt). Thus, the vehicle system is constructed such that the output voltage of the power supply system 20 does not depend on the magnitude of the three-phase AC power supplied from the power supply system 20 supplied to the traction motor 31.

  In addition to the fuel cell system 200, the DC-DC converter 64, and the drive circuit 36, the control unit 50 is electrically connected to a mode setting switch 51 (described later) provided in the vehicle 100, a vehicle speed sensor 52, a navigation system 53, and the like. They are connected to each other and execute various controls (including circuit control) and various input / output controls. Various control operations by the control unit 50 are realized by executing a computer program stored in a memory (not shown) built in the control unit 50 by, for example, an ECU (engine control unit) in the control unit 50. The Further, the memory is not particularly limited, and various recording media such as a ROM and a hard disk can be used.

  Here, an example of the control operation by the control unit 50 in the vehicle 100 will be further described. FIG. 3 is a flowchart showing an example of a procedure for adjusting and controlling the output of the fuel cell provided in the fuel cell system 200 by the control unit 50 in the first embodiment.

  In the present embodiment, first, when a user (driver or operator) of the vehicle 100 steps on the accelerator 37, the accelerator sensor 35 measures the amount of depression, that is, the accelerator opening Wt, and the measurement signal is sent to the control unit 50. Sent out. The controller 50 calculates the system power requirement of the fuel cell system 200 according to the accelerator opening Wt (step S11).

  Next, the control unit 50 calculates the required power A of the fuel cell based on the calculated system power requirement of the fuel cell system 200, and the power to be supplied from the secondary battery 26, that is, the necessity of the secondary battery 26. Electric power B is calculated (step S12). In other words, the power from the fuel cell system 200 is limited to the required power A with respect to the system required power of the fuel cell system 200, and the remaining required power B is supplemented from the secondary battery 26. Further, the control unit 50 calculates and sets the target voltage α of the fuel cell based on the calculated required power A of the fuel cell (step S13). Based on the running state of the vehicle, control is performed to change the target voltage and / or target potential fluctuation frequency (number of times) to be limited within a predetermined range.

  Then, the control unit 50 determines whether the calculated target voltage α of the fuel cell is larger than a predetermined voltage upper limit value β (α> β), and the target voltage α is a predetermined voltage lower limit value γ. Or less (α <γ) (step S14). At this time, the voltage upper limit value β and the voltage lower limit value γ are set or predicted in advance by, for example, empirical, experimental, simulation, or the like as the upper and lower limits of the potential band in which the performance degradation of the fuel cell is relatively difficult to occur. Can do.

  When it is determined in step S14 that the target voltage α of the fuel cell is larger than the voltage upper limit value β, the control unit 50 changes the target voltage of the fuel cell from the target voltage α to the target voltage β (step S14). S151), the control unit 50 controls the fuel cell voltage at that time to the target voltage β (step S152). Alternatively, when it is determined in step S14 that the target voltage α of the fuel cell is smaller than the voltage lower limit value γ, the control unit 50 changes the target voltage of the fuel cell from the target voltage α to the target voltage γ. (Step S171), the control unit 50 controls the fuel cell voltage at that time to the target voltage γ (step S172).

  On the other hand, in step S14, the target voltage α of the fuel cell is not larger than the voltage upper limit value β, and the target voltage α of the fuel cell is not smaller than the voltage lower limit value γ, that is, the target voltage α is lower than the voltage lower limit value γ. When it is determined that the voltage is equal to or lower than the voltage upper limit value β (γ ≦ α ≦ β), the control unit 50 changes the target voltage of the fuel cell from the target voltage α to the target voltage θ (step) S161). Then, the control unit 50 controls the fuel cell voltage at that time to the target voltage θ (step S162). Here, the target voltage θ is a value that is larger than the voltage lower limit value γ and smaller than the voltage upper limit value β (that is, γ <θ <β). That is, in this case, the initial target voltage α is multiplied by a predetermined “limitation rate R”, and as a result, the output of the fuel cell is limited to the target voltage θ.

  Here, FIG. 4 is a diagram schematically showing a relationship between the accelerator opening Wt and the total voltage of the fuel cell in the vehicle 100, and FIG. 5 is a fuel set for the accelerator opening Wt. It is a graph which shows an example of the limiting rate R mentioned above multiplied by the initial target voltage α of the battery. FIG. 6 is a schematic diagram (so-called map) showing the relationship between the voltage rise width (potential fluctuation width) and the voltage rise occurrence frequency (potential fluctuation occurrence frequency) of the fuel cell depending on the traveling state of the vehicle 100.

  As shown in the upper row labeled “Operation” in FIG. 4, during the operation of the vehicle 100, the accelerator opening Wt changes with time by the operation of the accelerator 37. The total voltage of the fuel cell in the fuel cell system 200 at that time fluctuates according to the accelerator opening Wt, as described in the middle stage labeled “Prior Art” in FIG.

  More specifically, when the accelerator 37 is depressed and the accelerator opening Wt is large, the total voltage of the fuel cell becomes relatively low. When the accelerator 37 is further depressed and the accelerator opening Wt approaches 100%, The required power increases rapidly and the total voltage of the fuel cell becomes very low (high potential). On the other hand, when the accelerator 37 is not depressed so much and the accelerator opening Wt is small, the total voltage of the fuel cell becomes relatively high. Decreases rapidly, and the total voltage of the fuel cell becomes extremely high (high potential).

  At that time, in the “prior art” shown in the middle of FIG. 4, the above-described potential fluctuation and the lower limit exceed the voltage upper limit β that is the upper limit of the potential band in which the performance degradation of the fuel cell is relatively difficult to occur. Even if a potential fluctuation that falls below the voltage lower limit γ occurs, the target voltage of the fuel cell as described with reference to the flow of FIG. 3 is not adjusted or controlled. On the other hand, according to the present embodiment of the present invention, the initial target voltage α of the fuel cell described above is changed to the target voltages β, γ, θ as shown as “present invention” in the lower part of FIG. In addition, the fuel cell voltages are controlled to their target voltages β, γ, θ. Therefore, the performance degradation of the fuel cell system 200 can be sufficiently suppressed.

  Further, as shown in FIG. 6, the voltage rise width of the fuel cell (up and down width of the total voltage of the fuel cell shown in FIG. 4) and the frequency of occurrence of voltage rise (the number of fluctuations in the vertical movement of the total voltage of the fuel cell shown in FIG. 4). Shows different behavior depending on the traveling state of the vehicle 100. The decrease in the performance of the fuel cell tends to become more prominent as the voltage increase width and / or the frequency of occurrence of the voltage increase becomes larger. From the contents shown in FIG. It tends to be different depending on the driving state depending on the difference (city area, suburb, highway, climbing slope, etc.).

  Since the degree of the accelerator operation, that is, the accelerator opening Wt naturally varies depending on the difference in the traveling state of the vehicle 100, in this embodiment, the initial target voltage of the fuel cell described in the explanation of FIG. It is also preferable to set the limiting rate R multiplied by α so as to change with respect to the accelerator opening Wt, for example, as shown in FIG. In other words, the control unit 50 performs control so that the fuel cell voltage rise and / or the voltage rise occurrence frequency decreases according to the accelerator opening Wt (control to reduce the number of fluctuations while narrowing the potential fluctuation range). I do.

  As a result, it is possible to further suppress the performance degradation of the fuel cell by suppressing the voltage rise width and / or frequency of occurrence of the voltage rise of the fuel cell, and to adjust the output voltage of the fuel cell according to the running state of the vehicle 100.・ It can be controlled.

(Second Embodiment)
FIG. 7 is a flowchart showing an example of a procedure for adjusting and controlling the output of the fuel cell provided in the fuel cell system 200 by the control unit 50 in the second embodiment of the fuel cell system of the present invention. In addition, since the structure of the vehicle provided with the fuel cell system of 2nd Embodiment is equivalent to 1st Embodiment shown in FIG.1 and FIG.2, the overlapping description here is abbreviate | omitted.

  The present embodiment is an example in which, for example, the relationship of the limiting rate R set with respect to the accelerator opening degree Wt shown in FIG. 5 is directly applied to the voltage control of the fuel cell. Accordingly, control for suppressing fluctuations in the voltage of the fuel cell (potential fluctuation suppression control) is performed.

  First, the control unit 50 calculates the system power requirement of the fuel cell system 200 according to the accelerator opening Wt (step S11), calculates the required power A of the fuel cell based on the system power requirement, The required power B to be supplied from the battery 26 is calculated (step S12). Then, the control unit 50 calculates and sets the target voltage α of the fuel cell based on the calculated required power A of the fuel cell (step S13). The steps so far are the same as those in the first embodiment shown in FIG.

  Further, the control unit 50 determines whether or not the fuel cell potential fluctuation suppression mode is set (step S24). For example, when the accelerator opening degree Wt is within a predetermined range set in advance, it is determined that the electric potential fluctuation control mode is set, and the accelerator opening degree Wt is determined to be the predetermined value. When it is not within the range (for example, when the accelerator opening Wt becomes equal to or greater than a certain value), it can be determined that the potential fluctuation control mode is not set. If it does in this way, the voltage control according to the usage method and driving method of the vehicle 100 by a user will be attained.

  If it is determined in step S24 that the current mode is not the potential fluctuation suppression mode (for example, when the accelerator opening Wt is equal to or greater than a certain value as described above), the initial target voltage α of the fuel cell is changed. Without doing so, the control unit 50 controls the fuel cell voltage to the target voltage α (step S36). On the other hand, if it is determined in step S24 that the potential fluctuation suppression mode is set, the control unit 50 limits the initial target voltage α of the fuel cell to the accelerator opening Wt at that time shown in FIG. The rate R is multiplied, and the control unit 50 controls the fuel cell voltage to the target voltage α × R (step S26). In the example of FIG. 5, when the accelerator opening Wt is greater than or equal to a certain value and less than or equal to a certain value, control is executed to reduce the restriction rate R and reduce the potential fluctuation of the fuel cell. .

  Even in the second embodiment including the control unit 50 that executes such control, the fuel cell voltage is appropriately controlled according to the accelerator opening Wt reflecting the traveling state of the vehicle 100. It is possible to prevent the fuel consumption of the vehicle 100 from deteriorating by reducing the load on the secondary battery 26 that supplements the power limit of the fuel cell system 200 while sufficiently suppressing the performance degradation. Further, when it is not necessary to execute the potential fluctuation suppression mode to limit the voltage of the fuel cell, such voltage fluctuation suppression control is not performed. Also in this respect, the fuel consumption of the vehicle 100 is deteriorated. Further suppression is possible.

(Third embodiment)
FIG. 8 is a flowchart showing an example of a procedure for adjusting and controlling the output of the fuel cell provided in the fuel cell system 200 by the control unit 50 in the third embodiment of the fuel cell system of the present invention. In addition, since the structure of the vehicle provided with the fuel cell system of 3rd Embodiment is also equivalent to 1st Embodiment shown in FIG.1 and FIG.2, the overlapping description here is abbreviate | omitted.

  The present embodiment is an example in which the voltage control of the fuel cell is performed in more detail in accordance with the accelerator operation depending on the traveling state of the vehicle 100 such as the road environment. In particular, the road environment is directly determined and the determination is performed. The result is fed back to the voltage control of the fuel cell.

  First, the control unit 50 calculates the system power requirement of the fuel cell system 200 according to the accelerator opening Wt (step S11), calculates the required power A of the fuel cell based on the system power requirement, The required power B to be supplied from the battery 26 is calculated (step S12). Then, the control unit 50 calculates and sets the target voltage α of the fuel cell based on the calculated required power A of the fuel cell (step S13). The steps so far are the same as those in the first embodiment shown in FIG.

  Furthermore, the control unit 50 determines whether or not the fuel cell potential fluctuation suppression mode is in accordance with the road environment (step S34). Specifically, for example, the following three modes are set in the mode setting switch 51 of the fuel cell so that the user of the vehicle 100 can freely select and switch between the modes.

・ Sport mode: Mode that uses the maximum performance of the fuel cell (no potential fluctuation suppression control)
Auto mode: A mode that controls the presence or absence and degree of voltage suppression of the fuel cell according to the user's usage and driving method of the vehicle 100 (automatic switching of presence or absence of potential fluctuation suppression control)
・ Soft mode: A mode that reduces the load applied to the fuel cell (with potential fluctuation suppression control)

  When the “sport mode” is selected by the mode setting switch 51 of the fuel cell, or when the “auto mode” is selected and the accelerator opening Wt is outside the predetermined range, the control unit 50 Thus, it is determined that the mode is not the potential fluctuation suppression mode, and the control unit 50 controls the fuel cell voltage to the target voltage α without changing the initial target voltage α of the fuel cell (step S36). On the other hand, when “auto mode” is selected by the mode setting switch 51 and the accelerator opening Wt is within a predetermined range set in advance, or when “soft mode” is selected, the control unit 50 controls the potential. It is determined that the fluctuation suppression mode is set.

  When it is determined that the potential fluctuation suppression mode is set, the control unit 50 executes a process for determining the road environment (step S35). The determination of the road environment is, for example, information about the external environment such as map data sent from the navigation system 53 to the control unit 50, such as an average vehicle speed calculated from the vehicle speed change sent from the vehicle speed sensor 52 to the control unit 50, step S11. This is performed based on information on the system required power (corresponding to the required average torque) calculated in step (1). These pieces of information can be used alone or in combination.

  Examples of the road environment include urban areas, suburbs, highways, uphills, and downhills shown in FIG. Table 1 shows an example of road environment determination.

  Here, FIG. 9 is a graph showing an example of the limiting rate R multiplied by the initial target voltage α of the fuel cell, which is set for the accelerator opening Wt according to the road environment. As shown in the figure, in this embodiment, the limiting rate R of the fuel cell voltage with respect to the accelerator opening Wt is set to be different depending on the road environment. In this example, when the road environment is an urban area, a suburb, and a highway, the limiting rates Ra, Rb, and Rc are adopted as the limiting rate R, respectively. The magnitude relationship between them is generally such that the limiting rate Ra <the limiting rate Rb <the limiting rate Rc.

  That is, when the road environment is an urban area (limitation rate Ra), the degree of control for suppressing the voltage rise (fluctuation) width and the voltage rise (fluctuation) occurrence frequency due to potential suppression is made relatively weak. On the other hand, when the road environment is a suburb (limitation rate Rb), the level of voltage increase due to potential suppression and the strength of control for suppressing the frequency of voltage increase are set to medium. On the other hand, when the road environment is a highway (restriction rate Rc), the degree of control for suppressing the voltage increase width due to potential suppression and the frequency of occurrence of voltage increase is made relatively strong.

  In order to realize such control, when it is determined in step S35 that the road environment is an urban area, the control unit 50 multiplies the initial target voltage α of the fuel cell by the limiting rate Ra, and the control unit 50 controls the fuel cell voltage to the target voltage α × Ra (step S37). On the other hand, when it is determined in step S35 that the road environment is a suburb, the control unit 50 multiplies the initial target voltage α of the fuel cell by the limiting rate Rb, and the control unit 50 sets the fuel cell voltage. The target voltage α × Rb is controlled (step S37). On the other hand, when it is determined in step S35 that the road environment is a highway, the control unit 50 multiplies the initial target voltage α of the fuel cell by the limiting rate Rc, and the control unit 50 determines the fuel cell voltage. Is controlled to the target voltage α × Rc (step S38).

  Also in the third embodiment including the control unit 50 that executes such control, the fuel cell voltage is appropriately controlled to reflect the traveling state of the vehicle 100, so that the performance degradation of the fuel cell system 200 is sufficiently suppressed. can do.

  Further, the fuel cell mode setting switch 51 can be provided to provide the user with many choices regarding the voltage control of the fuel cell and thus the output of the vehicle 100, thereby optimizing the running performance and fuel consumption of the vehicle 100. The user can select the potential fluctuation suppression control by himself / herself.

  In addition, as above-mentioned, this invention is not limited to the said embodiment, A various deformation | transformation is possible in the limit which does not change the summary. For example, the power supply system to which the control by the control unit 50 in each of the above-described embodiments can be applied is not limited to that illustrated in FIG. Further, altitude (elevation) data measured by an atmospheric pressure sensor or the like may be further used for determination of the road environment in step S35 of the third embodiment. Furthermore, in each embodiment, the control for adjusting the output of the fuel cell by operating the flow rate of the reaction gas supplied to the fuel cell system 200 may be combined. In this case, the control unit 50 executes the control. It may be configured.

  Furthermore, the configuration may be such that the degree of potential fluctuation suppression control can be weakened or canceled. Since the control for suppressing the potential fluctuation of the fuel cell suppresses the fuel cell output in response to the user's accelerator operation, the user may feel insufficient power. Therefore, if the degree of potential fluctuation suppression control can be weakened or canceled by the user's accelerator operation or the road environment, the user's preference can be further met.

  Further, in addition to the fuel cell mode setting switch 51, for example, an ECO (eco) mode switch may be added. As such an ECO mode switch, for example, various known controls that can improve the fuel consumption of the vehicle 100 can be set by changing the level of strength. Here, Table 2 shows an example of the fuel efficiency improvement effect when the potential fluctuation suppression control by the mode setting switch 51 described in the third embodiment and the control by a plurality of modes set in the ECO mode switch are combined. .

  As described above, according to the present invention, the load on the battery and the auxiliary equipment is reduced and the deterioration of the fuel consumption of the vehicle is suppressed while limiting the amount of change in the power generated by the fuel cell to prevent performance degradation. It becomes possible. Therefore, the present invention can be widely and effectively used for fuel cells in general, vehicles including fuel cells, equipment, systems, facilities, and the like, and the production thereof.

20 Power supply system 26 Secondary battery (battery)
28 Remaining capacity monitor 30 Load section 31 Traction motor 32 Gear mechanism 34 Wheel 35 Accelerator sensor 36 Drive circuit 37 Accelerator 50 Control section (control means)
51 Mode setting switch 51
52 Vehicle speed sensor 53 Navigation system 53
64 DC-DC converter 67 Ammeter 69 Voltmeter 100 Vehicle 200 Fuel cell system A Required power of fuel cell B Required power of secondary battery R Limiting rate Ra, Rb, Rc Limiting rate Wt Accelerator opening α, θ Target voltage β Voltage upper limit value γ Voltage lower limit value

Claims (1)

The present invention is a fuel cell system mounted on a vehicle,
A fuel cell;
Control means for controlling the output voltage of the fuel cell;
With
The control means calculates a system required power of the fuel cell system according to the accelerator opening of the vehicle, calculates a required power of the fuel cell based on the system required power, and based on the required power A target voltage and / or target potential fluctuation frequency of the fuel cell is set, and control is performed to change the target voltage and / or the target potential fluctuation frequency to be limited within a predetermined range based on the running state of the vehicle. Is,
Fuel cell system.

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