Fuel cell system

Abstract

To suppress deterioration of NV due to hunting of generated electric energy, and to suppress deterioration of a cell of a fuel cell, in a fuel cell system controlling the generated electric energy by controlling operation of an auxiliary machine.SOLUTION: The fuel cell system 1 includes the fuel cell FC, the controller 3 that controls the amount of power generated by the fuel cell FC by controlling the operation of the first auxiliary device AM1 to the third auxiliary device AM3 related to the fuel cell FC, and the first temperature sensor TH1, the second temperature sensor TH2, and the third temperature sensor TH3 that acquire the temperature of the fuel cell FC. The control unit 3 calculates the temperatures of the first accessory TH1, the second accessory TH2, and the third accessory TH3 based on the temperatures acquired by the first temperature sensor AM1, the second temperature sensor AM3, and the third temperature sensor AM1, respectively, and performs power generation amount adjustment control for limiting the amount of power generation when the temperatures of the first accessory AM3, the second accessory LA, and the third accessory LA are equal to or higher than a predetermined temperature condition.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a fuel cell system. [Background technology]

[0002] For example, in power sources installed in vehicles, it is necessary to prevent overheating for safety reasons. For example, Patent Document 1 discloses a technology that can prevent overheating by suppressing output when signs of overheating begin to appear.

[0003] In the above technology, by adding the coolant temperature to the control factors, when the coolant temperature is above a predetermined temperature, the amount of power generated is controlled based on the lower of the upper limit power generation amount, which decreases as the coolant temperature rises, or the target power generation amount. This prevents the vehicle engine from overheating or overcooling, prevents the vehicle battery from overcharging, and avoids giving the user an unnatural impression. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 8-168103 Summary of the Invention [Problem to be solved by the invention]

[0005] Even in a fuel cell system equipped with a fuel cell as a power source (electric power supply source), overheating of auxiliary components is a possibility, and therefore it is necessary to control the temperature using a technique similar to that of Patent Document 1.

[0006] However, when a fuel cell is used as a power source, if the output of generated power is controlled to be reduced when signs of overheating begin to appear, as with the technology in Patent Document 1, the amount of power generated by the fuel cell may fluctuate depending on the heat capacity and heat generation characteristics of the auxiliary components, which may result in a worsening of the vehicle's NV (Noise Vibration) and accelerated deterioration of the fuel cell cells.

[0007] An object of one aspect of the present invention is to suppress deterioration of NV due to hunting in the amount of power generated, and to suppress deterioration of fuel cell cells, in a fuel cell system that controls the amount of power generated by controlling the operation of auxiliary equipment. [Means for solving the problem]

[0008] One form of the fuel cell system according to the present invention comprises a fuel cell unit, a control unit that controls the amount of power generated by the fuel cell unit by controlling the operation of multiple auxiliary devices associated with the fuel cell unit, and a temperature acquisition means that acquires the temperature of the fuel cell unit, wherein the control unit calculates the temperature of each of the multiple auxiliary devices based on the temperature acquired by the temperature acquisition means, and when the temperature of each of the multiple auxiliary devices exceeds a predetermined temperature condition, performs power generation adjustment control that limits the amount of power generated.

[0009] This makes it possible to suppress deterioration of NV due to hunting of the amount of generated power, and also to suppress deterioration of the fuel cell.

[0010] Furthermore, one embodiment of the fuel cell system according to the present invention comprises a fuel cell unit, a control unit that controls the amount of power generated by the fuel cell unit by controlling the operation of auxiliary equipment associated with the fuel cell unit, and a temperature acquisition means that acquires a temperature associated with the fuel cell unit, wherein the control unit performs power generation adjustment control to limit the amount of power generated when the temperature acquired by the temperature acquisition means exceeds a predetermined temperature condition, and the auxiliary equipment includes at least a fuel cell, an air compressor, and a DC-DC converter.

[0011] This makes it possible to suppress deterioration of NV due to hunting of the amount of generated power, and also to suppress deterioration of the fuel cell.

[0012] Furthermore, one form of the fuel cell system according to the present invention comprises a fuel cell unit, a control unit that controls the amount of power generated by the fuel cell unit by controlling the operation of a plurality of auxiliary devices associated with the fuel cell unit, and a temperature acquisition means that acquires a temperature associated with the fuel cell unit, wherein the control unit performs power generation adjustment control that limits the amount of power generated when the temperature acquired by the temperature acquisition means exceeds a predetermined temperature condition, and the control unit performs the power generation control based on the same limit rate map that is pre-stored for each of the plurality of auxiliary devices.

[0013] This makes it possible to suppress deterioration of NV due to hunting of the amount of generated power, and also to suppress deterioration of the fuel cell. [Effects of the Invention]

[0014] According to the present invention, in a fuel cell system that controls the amount of power generated by controlling the operation of auxiliary equipment, it is possible to suppress deterioration of NV due to hunting in the amount of power generated, and to suppress deterioration of the fuel cell cells. [Brief explanation of the drawings]

[0015] [Figure 1]1 is a diagram illustrating an example of a fuel cell system according to an embodiment. [Figure 2] FIG. 4 is a diagram illustrating an example of power generation amount adjustment control performed by a control unit. [Figure 3] FIG. 10 is a diagram illustrating an example of a restriction rate map. [Figure 4] FIG. 10 is a diagram showing the relationship between the control period in which the limit rate is updated and the period in which the power generation amount limit rate is updated. [Figure 5] 10 is a flowchart showing an example of a limit rate acquisition process in the power generation amount adjustment control executed by the control unit. [Figure 6] 10 is a flowchart showing an example of a power generation amount calculation process in the power generation amount adjustment control executed by the control unit. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, the embodiments will be described in detail with reference to the drawings.

[0017] FIG. 1 is a diagram illustrating an example of a fuel cell system according to an embodiment.

[0018] 1 is mounted on a vehicle Ve, such as an industrial vehicle such as a forklift, an automobile, etc. The vehicle Ve is equipped with an external load Lo, such as an inverter that drives a traction motor, and power is supplied from the fuel cell system 1 to the external load Lo.

[0019] The fuel cell system 1 includes a fuel cell (fuel cell unit) FC, a fuel tank T, and an air compressor ACP.

[0020] The fuel cell system 1 further includes a radiator R, a fan F, a water pump WP, a DC-DC converter CNV, a power storage device B, a current sensor Sif, a voltage sensor Svf, a memory unit 2, a control unit 3, a first temperature sensor TH1 (temperature acquisition means), a second temperature sensor TH2 (temperature acquisition means), and a third temperature sensor TH3 (temperature acquisition means).

[0021] The fuel cell system 1 outputs electric power to an external load Lo and the like based on auxiliary equipment, which is equipment having auxiliary functions required when the fuel cell FC generates power. The auxiliary equipment is equipment related to the fuel cell FC. The auxiliary equipment includes a fuel tank T, an air compressor ACP, a radiator R, a fan F, a water pump WP, a DC-DC converter CNV, a power storage device B, and the like. In this embodiment, the auxiliary equipment may include the fuel cell FC itself. The auxiliary equipment may also include other equipment not shown in FIG. 1.

[0022] A fuel cell FC is a fuel cell made up of multiple fuel cell units connected in series with each other, and generates electricity through an electrochemical reaction between hydrogen contained in a fuel gas (such as hydrogen gas) and oxygen contained in an oxidant gas (such as air).

[0023] The fuel tank T is a storage container for fuel gas. The fuel gas stored in the fuel tank T is supplied to the fuel cell FC.

[0024] The air compressor ACP compresses the oxidant gas present around the fuel cell system 1 and supplies it to the fuel cell FC. The compression rate of the air compressor ACP is controlled by adjusting the opening of a valve provided downstream of the fuel cell FC.

[0025] The radiator R exchanges heat between the refrigerant, which has been heated by the heat generated by the fuel cell FC, and the outside air.

[0026] The fan F blows cooling air onto the radiator R, thereby increasing the amount of heat dissipated by the radiator R.

[0027] The water pump WP supplies the refrigerant cooled by the radiator R to the fuel cell FC.

[0028] The DC-DC converter CNV is connected downstream of the fuel cell FC and converts the voltage Vfc (e.g., 90 [V]) output from the fuel cell FC into a voltage Vch (e.g., 48 [V]). The power output from the DC-DC converter CNV is supplied to an external load Lo, an internal load Li, and a power storage device B. The internal load Li includes an air compressor ACP, a water pump WP, a fan F, and the like. The internal load Li may also include other devices not shown in FIG. 1.

[0029] The power storage device B is configured by a lithium ion capacitor, a lithium ion secondary battery, or the like, and is connected between the DC-DC converter CNV and the external load Lo.

[0030] When the supply power corresponding to the difference between the power output from the DC-DC converter CNV and the total value of the power supplied to the internal load Li is greater than the power required by the external load Lo, the power corresponding to the required power is supplied to the external load Lo, and the remaining power is supplied to the power storage device B. When power is supplied from the DC-DC converter CNV to the power storage device B, the power storage device B is charged and the SOC (State Of Charge) of the power storage device B increases. Also, when the supply power corresponding to the difference between the power output from the DC-DC converter CNV and the total value of the power supplied to the internal load Li is smaller than the power required by the external load Lo, the supply power is supplied to the external load Lo, and the shortfall in power is supplied from the power storage device B to the external load Lo. When power is supplied from the power storage device B to the external load Lo, the power storage device B is discharged and the SOC of the power storage device B decreases. The SOC may be the charging rate [%] of the storage device B (the ratio of the remaining capacity to the fully charged capacity of the storage device B), or the open circuit voltage [V] of the storage device B when no current is flowing to the storage device B, or the closed circuit voltage [V] of the storage device B when current is flowing to the storage device B, or the integrated value [Ah] of the current flowing to the storage device B, etc.

[0031] The current sensor Sif is configured with a shunt resistor, a Hall element, etc., and detects the current Ifc flowing from the fuel cell FC to the DC-DC converter CNV, and sends the detected current If to the control unit 3.

[0032] The voltage sensor Svf is configured with a voltage dividing resistor and the like, detects the voltage Vfc of the fuel cell FC, and sends the detected voltage Vfc to the control unit 3.

[0033] The first temperature sensor TH1, the second temperature sensor TH2, and the third temperature sensor TH3 (hereinafter also referred to as "temperature sensors") acquire the temperatures of the respective auxiliary devices (hereinafter also referred to as "auxiliary device temperatures") associated with the fuel cell system 1. The first temperature sensor TH1, the second temperature sensor TH2, and the third temperature sensor TH3 are configured, for example, by thermistors. The first temperature sensor TH1, the second temperature sensor TH2, and the third temperature sensor TH3 each send the acquired auxiliary device temperatures to the control unit 3.

[0034] The first temperature sensor TH1 acquires the temperature of the fuel cell FC (hereinafter also referred to as "first auxiliary machine AM1"). For example, the first temperature sensor TH1 can acquire the temperature of the fuel cell FC (hereinafter also referred to as "first auxiliary machine temperature AT1") by acquiring the temperature of the coolant warmed by the heat generated by the fuel cell FC. The first temperature sensor TH1 sends the acquired first auxiliary machine temperature AT1 to the control unit 3.

[0035] The second temperature sensor TH2 acquires the temperature of the air compressor ACP (hereinafter also referred to as the "second accessory AM2"). For example, the second temperature sensor TH2 can acquire the temperature of the air compressor ACP (hereinafter also referred to as the "second accessory temperature AT2") by measuring the temperature near the air compressor ACP. The second temperature sensor TH2 sends the acquired second accessory temperature AT2 to the control unit 3.

[0036] The third temperature sensor TH3 acquires the temperature of the DC-DC converter CNV (hereinafter also referred to as the "third auxiliary device AM3"). For example, the third temperature sensor TH3 can acquire the temperature of the DC-DC converter CNV (hereinafter also referred to as the "third auxiliary device temperature AT3") by measuring the temperature of a MOSFET (metal-oxide-semiconductor field-effect transistor) that configures the DC-DC converter CNV. The third temperature sensor TH3 sends the acquired third auxiliary device temperature AT3 to the control unit 3.

[0037] The storage unit 2 is configured with RAM (Random Access Memory), ROM (Read Only Memory), etc. The storage unit 2 stores a limit rate map that is set based on the auxiliary temperatures (first auxiliary temperature AT1, second auxiliary temperature AT2, third auxiliary temperature AT3). The limit rate map is set for each auxiliary. The limit rate map will be described in detail later.

[0038] The control unit 3 is configured by a microcomputer and the like.

[0039] Furthermore, the control unit 3 changes the power generation amount target value TPG in stages according to the SOC of the power storage device B while the fuel cell system 1 is operating.

[0040] Furthermore, the control unit 3 controls the operation of the internal load Li so that the power generated by the fuel cell FC follows the power generation target value TPG when the fuel cell system 1 is operating. For example, when the fuel cell system 1 is operating, the control unit 3 controls the operation of the internal load Li by PI (Proportional-Integral) control so that the difference between the power generated by the fuel cell FC and the power generation target value TPG becomes zero.

[0041] The control unit 3 controls the amount of power generated by the fuel cell FC by controlling the operation of the auxiliaries associated with the fuel cell FC. When the temperatures of the auxiliaries (first auxiliaries temperature AT1, second auxiliaries temperature AT2, third auxiliaries temperature AT3) acquired by the temperature sensors (first temperature sensor TH1, second temperature sensor TH2, third temperature sensor TH3) reach or exceed a predetermined temperature (t1) condition, the control unit 3 performs power generation adjustment control to limit the amount of power generated.

[0042] Fig. 2 is a diagram showing an example of power generation amount adjustment control performed by the control unit 3. The control unit 3 has a different limit rate map for each auxiliary device. In Fig. 2, the control unit 3 has a first limit rate map MP1, a second limit rate map MP2, and a third limit rate map MP3 as the limit rate maps. The limit rate maps are not limited to those shown in Fig. 2. The same limit rate map may be used for each auxiliary device.

[0043] The control unit 3 acquires the limiting rates from the limiting rate maps (first limiting rate map MP1, second limiting rate map MP2, third limiting rate map MP3). For example, the control unit 3 determines whether or not auxiliary temperatures (first auxiliary temperature AT1, second auxiliary temperature AT2, third auxiliary temperature AT3) have been sent from temperature sensors (first temperature sensor TH1, second temperature sensor TH2, third temperature sensor TH3) that measure the temperatures of the auxiliary machines. If the auxiliary temperatures have been sent from the temperature sensors, the control unit 3 acquires the sent auxiliary temperatures (first auxiliary temperature AT1, second auxiliary temperature AT2, third auxiliary temperature AT3). Then, the control unit 3 refers to the limiting rate map corresponding to the acquired auxiliary machine, and acquires the limiting rate of the corresponding auxiliary machine.

[0044] Fig. 3 is a diagram showing an example of a restriction rate map. The restriction rate map has a first restriction rate set based on the restriction rate and the accessory temperature. Fig. 3 explains the first restriction rate map MP1 as an example of the restriction rate map. The second restriction rate map MP2 and the third restriction rate map MP3 have the same configuration as the first restriction rate map MP1, and therefore explanations thereof will be omitted.

[0045] In the first limit rate map MP1 of FIG. 3, temperature t1 (first temperature threshold) indicates the temperature at which limitation by power generation amount adjustment control begins (hereinafter also referred to as the "limitation start temperature"). Temperature t2 (second temperature threshold) indicates the maximum temperature at which limitation by power generation amount adjustment control is permitted (hereinafter also referred to as the "maximum limit temperature"). Temperature t3 (third temperature threshold) indicates the threshold temperature (diagnosis determination temperature) at which a malfunction of the fuel cell system 1 is determined. Temperature t2 is set between temperature t3 and temperature t1. For example, temperature t2 may be set midway between temperature t3 and temperature t1.

[0046] 3, the normal limit rate NLR indicates a state in which no limit is applied, and for example, a relationship of "normal limit rate NLR = 1" is set. The lower limit limit rate LLR indicates a state in which a maximum limit is applied, and for example, a relationship of "1 > lower limit limit rate LLR > 0" is set.

[0047] The control unit 3 fixes the limit rate to the normal limit rate NLR by referring to the limit rate map in FIG. 3 until the acquired first auxiliary temperature AT1 reaches temperature t1. That is, no limit is applied until the auxiliary temperature reaches temperature t1. When the acquired first auxiliary temperature AT1 exceeds temperature t1, the control unit 3 linearly decreases the limit rate as the acquired first auxiliary temperature AT1 increases. That is, the control unit 3 gradually decreases the limit rate from the normal limit rate NLR to LR2. Then, when the acquired first auxiliary temperature AT1 reaches temperature t2, the control unit 3 fixes the limit rate to LR2. Because the limit rate linearly decreases as the auxiliary temperature increases based on the limit rate map, the control unit 3 can set an appropriate amount of power generation.

[0048] As described above, the control unit 3 does not impose any restrictions until the auxiliary temperature reaches temperature t1. When the auxiliary temperature exceeds temperature t1, a restriction rate that decreases linearly as the auxiliary temperature rises is applied, and when the auxiliary temperature exceeds temperature t2, the restriction rate is set constant as the lower limit restriction rate LLR. This makes it possible to ensure a certain amount of necessary power generation even when the auxiliary temperature exceeds a certain level, and to take evacuation measures such as moving the vehicle to an evacuation location.

[0049] The control unit 3 updates each limit rate (first limit rate LR1, second limit rate LR2, third limit rate LR3) based on the limit rate maps (first limit rate map MP1, second limit rate map MP2, third limit rate map MP3). The control unit 3 then determines the smallest limit rate among the updated limit rates (first limit rate LR1, second limit rate LR2, third limit rate LR3) as the power generation amount limit rate PLR. The power generation amount limit rate PLR ​​is a ratio for implementing power generation amount adjustment control. For example, if the acquired first limit rate LR1 = "1", second limit rate LR2 = "0.9", and third limit rate LR3 = "0.8", the control unit 3 determines the smallest third limit rate LR3 = "0.8" as the power generation amount limit rate PLR.

[0050] The control unit 3 calculates the final target power amount FTP by multiplying the acquired limit rates (first limit rate LR1, second limit rate LR2, third limit rate LR3) by the maximum power generation amount (maximum power generation) MPG. For example, the control unit 3 calculates the final target power amount FTP by multiplying the power generation amount limit rate PLR ​​determined based on the updated limit rates (first limit rate LR1, second limit rate LR2, third limit rate LR3) by the maximum power generation amount MPG. The maximum power generation amount MPG is the maximum amount of power generation that can be output by the fuel cell FC. The maximum power generation amount MPG is set in advance in accordance with the fuel cell FC.

[0051] The control unit 3 compares the calculated final target power amount FTP with the power generation amount PGS determined from the SOC (State of Charge) of the power storage device B, and controls the power generation amount of the fuel cell FC through power generation amount adjustment control. Specifically, the control unit 3 calculates the smaller value of the calculated final target power amount FTP or the power generation amount PGS determined from the SOC as the power generation amount target value TPG.

[0052] The power generation amount PGS determined from the SOC is determined based on the SOC of the power storage device B and the amount of power required by the external load Lo. Then, the control unit 3 controls the amount of power generated by the fuel cell FC based on the calculated power generation amount target value TPG.

[0053] FIG. 4 is a diagram showing the relationship between the control period in which the limit rates (first limit rate LR1, second limit rate LR2, third limit rate LR3) are updated and the period in which the power generation amount limit rate PLR ​​is updated.

[0054] When auxiliary temperatures (first auxiliary temperature AT1, second auxiliary temperature AT2, third auxiliary temperature AT3) are sent from the temperature sensors (first temperature sensor TH1, second temperature sensor TH2, third temperature sensor TH3) that measure each auxiliary (first auxiliary AM1, second auxiliary AM2, third auxiliary AM3), the control unit 3 begins to impose restrictions through power generation adjustment control.

[0055] For example, at time T11 when the first auxiliary temperature AT1 is received from the first temperature sensor TH1 that measures the temperature of the first auxiliary AM1, the control unit 3 references the first limiting rate map MP1 that corresponds to the first auxiliary temperature AT1 and starts updating the first limiting rate LR1 of the first auxiliary AM1. Thereafter, at times T12 and T13 when the first auxiliary temperature AT1 is received from the first temperature sensor TH1, the control unit 3 updates the first limiting rate LR1 of the first auxiliary AM1. Therefore, the control unit 3 can update the first limiting rate LR1 of the first auxiliary AM1 in a first cycle CY1 (control cycle) that is the times T11, T12, and T13 when the first auxiliary temperature AT1 is received.

[0056] Furthermore, at time T21 when the second auxiliary temperature AT2 is received from the second temperature sensor TH2 that measures the temperature of the second auxiliary AM2, the control unit 3 references the second limiting rate map MP2 that corresponds to the second auxiliary temperature AT2 and starts updating the second limiting rate LR2 of the second auxiliary AM2. Thereafter, at time T22 when the second auxiliary temperature AT2 is received from the second temperature sensor TH2, the control unit 3 updates the second limiting rate LR2 of the second auxiliary AM2. Finally, at time T23 when the second auxiliary temperature AT2 is received from the second temperature sensor TH2, the control unit 3 finishes updating the second limiting rate LR2 of the second auxiliary AM2. Therefore, the control unit 3 can update the second limiting rate LR2 of the second auxiliary AM2 in the second cycle CY2 (control cycle) of times T21, T22, and T23 when the second auxiliary temperature AT2 is received.

[0057] Furthermore, at time T31 when the third auxiliary temperature AT3 is received from the third temperature sensor TH3 that measures the temperature of the third auxiliary AM3, the control unit 3 references the third limit rate map MP3 that corresponds to the third auxiliary temperature AT3 and starts updating the third limit rate LR3 of the third auxiliary AM3. Thereafter, at times T32, T33, and T34 when the third auxiliary temperature AT3 is received from the third temperature sensor TH3, the control unit 3 updates the third limit rate LR3 of the third auxiliary AM3. Therefore, the control unit 3 can update the third limit rate LR3 of the third auxiliary AM3 in a third cycle CY3 (control cycle) that is the times T31, T32, T33, and T34 when the third auxiliary temperature AT3 is received.

[0058] The control unit 3 determines the power generation amount limit rate PLR ​​based on the first limit rate LR1, the second limit rate LR2, and the third limit rate LR3. The control unit 3 determines the power generation amount limit rate PLR ​​based on the smallest limit rate among the updated limit rates. If limit update has not started, the first limit rate LR1, the second limit rate LR2, and the third limit rate LR3 are set to "1" as their initial values. In other words, if update of any of the first limit rate LR1, the second limit rate LR2, and the third limit rate LR3 has not started, the control unit 3 determines "1" as the power generation amount limit rate PLR.

[0059] The control unit 3 then starts determining the power generation limit rate PLR ​​at an arbitrary time T01. The arbitrary time T01 may be the same time as the time when an update of any of the limit rates started (for example, time T11). The control unit 3 then determines the power generation limit rate PLR ​​in a cycle CY0 until the next arbitrary time T02.

[0060] For example, a case will be described where the first limit rate LR1 is updated to "0.9" at time T11. The control unit 3 determines the power generation limit rate PLR ​​based on the smallest limit rate at time T01 (=time T11). In this case, since only the first limit rate LR1 has been updated at time T01, the second limit rate LR2 and the third limit rate LR3 are both "1". Therefore, the control unit 3 determines the first limit rate LR1 of "0.9", which is the smallest limit rate, as the power generation limit rate PLR.

[0061] Furthermore, at time T02 after cycle CY0, if the first limiting rate LR1 is "0.9", the second limiting rate LR2 is "0.8", and the first limiting rate LR1 is "1.0", the control unit 3 determines the smallest limiting rate, the second limiting rate LR2 "0.8", as the power generation limiting rate PLR.

[0062] As described above, the power generation limit rate PLR ​​of the fuel cell FC can be determined based on the smallest limit rate among the limit rates calculated based on the auxiliary temperature, so the control unit 3 can precisely set an appropriate power generation amount.

[0063] Furthermore, the limit rates (first limit rate LR1, second limit rate LR2, third limit rate LR3) used in the power generation adjustment control are updated over a predetermined control period (first period CY1, second period CY2, third period CY3). The period CY0 for determining the power generation limit rate PLR ​​is set longer than the control periods (first period CY1, second period CY2, third period CY3) for the limit rates (first limit rate LR1, second limit rate LR2, third limit rate LR3) used in the power generation adjustment control. This reduces noise fluctuations from the auxiliary equipment and improves noise vibration (NV) characteristics. Suppressing fluctuations in the limit rates of each auxiliary equipment, which change constantly, suppresses power generation hunting, reduces deterioration of vibration and noise performance, which helps stabilize power generation, and suppresses deterioration of the fuel cell stack.

[0064] Furthermore, the limit rates (first limit rate LR1, second limit rate LR2, third limit rate LR3) used in the power generation adjustment control are updated at control intervals (first cycle CY1, second cycle CY2, third cycle CY3) after a predetermined time has elapsed. Therefore, the control periods of the control rates (first limit rate LR1, second limit rate LR2, third limit rate LR3) used in the power generation adjustment control can be set arbitrarily according to the thermal capacity at which the operation of each auxiliary device does not become hunting.

[0065] 5 and 6 are flowcharts showing an example of the power generation amount adjustment control process executed by the control unit 3. Fig. 5 is a flowchart showing an example of the limit rate acquisition process of the power generation amount adjustment control executed by the control unit 3. The limit rate acquisition process described in Fig. 5 is executed separately and independently from the power generation amount calculation process described in Fig. 6. The limit rate acquisition process described in Fig. 5 may be executed in series with the power generation amount calculation process described in Fig. 6.

[0066] The limit rate acquisition process described in Fig. 5 is started, for example, when the ignition is turned on. In the flowchart of Fig. 5, first, the control unit 3 determines whether or not an auxiliary temperature has been sent from a temperature sensor (step S11). In this process, the control unit 3 determines whether or not an auxiliary temperature (first auxiliary temperature AT1, second auxiliary temperature AT2, third auxiliary temperature AT3) has been sent from any of the multiple temperature sensors (first temperature sensor TH1, second temperature sensor TH2, third temperature sensor TH3).

[0067] If the auxiliary temperature is not received from any of the temperature sensors (step S11: No), the control unit 3 waits for processing. If the auxiliary temperature is received from any of the temperature sensors (step S11: Yes), the control unit 3 acquires the auxiliary temperature received from the temperature sensor (step S12).

[0068] The control unit 3 updates the limit rate of the corresponding auxiliary device by referring to a limit rate map corresponding to the auxiliary device temperature acquired in step S12 (step S13). In this process, for example, when a first auxiliary device temperature AT1 is received from the first temperature sensor TH1, the control unit 3 updates the first limit rate LR1 as the limit rate of the fuel cell FC corresponding to the first temperature sensor TH1 by referring to the first limit rate map MP1. The resource rate used for power generation adjustment control is updated with a predetermined time period as a control period. The control period for updating the limit rate differs for each auxiliary device. Therefore, the control period for updating the limit rate may differ for each auxiliary device. Furthermore, in the case of the same type of auxiliary device, the control unit 3 may update the limit rate at the same control period. For example, the control unit 3 may update the limit rate by referring to different limit rate maps depending on the thermal capacity of the auxiliary device. Note that the period for updating the power generation amount target value is set longer than the control period for the limit rate. This stabilizes power generation by the fuel cell FC and suppresses cell deterioration of the fuel cell FC. Furthermore, noise fluctuations from the auxiliary devices can be reduced, improving NV characteristics.

[0069] Also, for example, when the second accessory temperature AT2 is sent from the second temperature sensor TH2, the control unit 3 refers to the second restriction rate map MP2 and updates the second restriction rate LR2 as the restriction rate of the air compressor ACP corresponding to the second temperature sensor TH2.

[0070] Also, for example, when the third auxiliary temperature AT3 is sent from the third temperature sensor TH3, the control unit 3 refers to the third limiting rate map MP3 and updates the third limiting rate LR3 as the limiting rate of the DC-DC converter CNV corresponding to the third temperature sensor TH3.

[0071] Each time an auxiliary temperature (first auxiliary temperature AT1, second auxiliary temperature AT2, third auxiliary temperature AT3) is sent from the temperature sensors (first temperature sensor TH1, second temperature sensor TH2, third temperature sensor TH3), the control unit 3 repeatedly executes the processing of steps S11 to S13 to update each limiting rate (first limiting rate LR1, second limiting rate LR2, third limiting rate LR3).

[0072] Fig. 6 is a flowchart showing an example of the power generation amount calculation process in the power generation amount adjustment control executed by the control unit 3. The power generation amount calculation process explained in Fig. 6 is executed separately and independently from the limit rate acquisition process explained in Fig. 5. The power generation amount calculation process explained in Fig. 6 may be executed in series with the limit rate acquisition process explained in Fig. 5.

[0073] 6, first, the control unit 3 determines the smallest limit rate among the limit rates updated by the control unit 3 as the power generation amount limit rate PLR ​​(step S21). For example, the control unit 3 determines the power generation amount limit rate PLR ​​based on the smallest limit rate among the currently updated first limit rate LR1, second limit rate LR2, and third limit rate LR3.

[0074] The control unit 3 multiplies the power generation amount limit rate PLR ​​determined in step S21 by the maximum power generation amount MPG of the fuel cell FC to calculate the final target power amount FTP (step S22).

[0075] The control unit 3 compares the final target power amount FTP calculated in step S22 with the power generation amount PGS determined from the SOC of the power storage device B, and calculates the smaller value as the power generation amount target value TPG (step S23). Based on the calculated (updated) power generation amount target value TPG, the control unit 3 can control the amount of power generated by the fuel cell FC by controlling each auxiliary device.

[0076] The control unit 3 determines whether a predetermined time has passed since the previous power generation amount limit rate PLR ​​was determined in the process of step S21 (step S24). If the predetermined time has not passed since the previous power generation amount limit rate PLR ​​was determined (step S24: No), the process goes to standby. If the predetermined time has passed since the previous power generation amount limit rate PLR ​​was determined (step S24: Yes), the process returns to step S21, and the processes of steps S21 to S24 are repeatedly executed. In other words, the power generation amount limit rate PLR ​​is continuously updated at predetermined intervals.

[0077] The present invention is not limited to the above-described embodiments, and various improvements and modifications can be made without departing from the spirit and scope of the present invention.

[0078] <Variation 1> 1 shows only three temperature sensors (first temperature sensor TH1, second temperature sensor TH2, and third temperature sensor TH3), this is not a limitation and at least one temperature sensor may be required. The first temperature sensor TH1, second temperature sensor TH2, and third temperature sensor TH3 may acquire the temperature of the fuel cell FC, and the restriction rate of each auxiliary device may be calculated based on that temperature.

[0079] <Variation 2> The fuel cell system 1 in the above embodiment is configured as a generator that supplies power to an external load Lo mounted on a vehicle Ve, but the fuel cell system 1 may also be configured as a stationary generator that cooperates with a commercial power source to supply power to an external load Lo located outside the fuel cell system 1.

[0080] <Variation 3> In the above embodiment, when the acquired auxiliary temperature exceeds temperature t1, the control unit 3 of the fuel cell system 1 linearly decreases the power generation limit rate as the acquired auxiliary temperature increases. However, the power generation limit rate may be set in stages rather than linearly. This makes it easier to control the power generation amount. Alternatively, the limit rate may be decreased quadratically as the acquired auxiliary temperature increases. This makes it possible to ensure a certain amount of power generation while suppressing the possibility of the fuel cell system 1 or the auxiliary equipment overheating. [Explanation of symbols]

[0081] 1: Fuel cell system 2: Storage section 3: Control section ACP: Air Compressor AM1: First auxiliary engine AM2: Second auxiliary engine AM3: Third auxiliary engine AT1: First auxiliary temperature AT2: Second auxiliary temperature AT3: Third auxiliary temperature B:Power storage device CNV: DC / DC converter CY0: Cycle CY1: 1st cycle CY2: 2nd cycle CY3: 3rd cycle F: Fan FC: Fuel cell FTP:Final target power amount If: Current Ifc: Current LLR: Lower Limit Rate LR1: First limit rate LR2: Second limit rate LR3: Third restriction rate Li: Internal load Lo: External load MP1: 1st limit rate map MP2: Second limit rate map MP3: 3rd Limit Rate Map MPG: Maximum power generation NLR: Normal Limit Rate PGS: Power generation PLR: Power generation limit rate R: Radiator Sif: Current sensor Svf: Voltage sensor T: Fuel tank TH1: First temperature sensor TH2: Second temperature sensor TH3: Third temperature sensor TPG: Target power generation amount Vch: Voltage Ve: Vehicle Vfc: Voltage WP: Water pump

Claims

1. a fuel cell unit; a control unit that controls the amount of power generated by the fuel cell unit by controlling the operation of a plurality of auxiliary devices associated with the fuel cell unit; a temperature acquisition means for acquiring the temperature of the fuel cell unit, The control unit calculates the temperature of each of the plurality of auxiliary machines based on the temperature acquired by the temperature acquisition means, and when the temperature of each of the plurality of auxiliary machines exceeds a predetermined temperature condition, performs power generation adjustment control to limit the amount of power generated.

2. a fuel cell unit; a control unit that controls the amount of power generated by the fuel cell unit by controlling the operation of auxiliary devices associated with the fuel cell unit; a temperature acquisition means for acquiring a temperature related to the fuel cell unit; the control unit performs power generation amount adjustment control to limit the amount of power generation when the temperature acquired by the temperature acquisition means becomes equal to or higher than a predetermined temperature condition; The fuel cell system is characterized in that the auxiliary equipment includes at least a fuel cell, an air compressor, and a DC-DC converter.

3. a fuel cell unit; a control unit that controls the amount of power generated by the fuel cell unit by controlling the operation of a plurality of auxiliary devices associated with the fuel cell unit; a temperature acquisition means for acquiring a temperature related to the fuel cell unit; the control unit performs power generation amount adjustment control to limit the amount of power generation when the temperature acquired by the temperature acquisition means becomes equal to or higher than a predetermined temperature condition; The fuel cell system is characterized in that the control unit controls the amount of power generation based on the same limit rate map stored in advance for each of the plurality of auxiliary machines.

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