Fuel cell system

Abstract

To provide a fuel cell system that controls generated electric energy by controlling an operation of an auxiliary device, in which the aggravation of NV due to hunting of the generated electric energy is suppressed and the deterioration of a cell of a fuel cell is suppressed.SOLUTION: A fuel cell system 1 includes: a fuel cell FC; a control unit 3 that controls the electric energy generated by the fuel cell FC by controlling operations of a first auxiliary device AM1 to a third auxiliary device AM3 which relate to the fuel cell FC; and a first temperature sensor TH1, a second temperature sensor TH2, and a third temperature sensor TH3 that acquire temperatures of the auxiliary devices of the first auxiliary device AM1, the second auxiliary device AM2, and the third auxiliary device AM3 which relate to the fuel cell FC. When a first auxiliary device temperature AT1, a second auxiliary device temperature AT2, and a third auxiliary device temperature AT3 which are acquired by the first temperature sensor TH1, the second temperature sensor TH2, and the third temperature sensor TH3, respectively, become a temperature t1 condition or higher, the control unit 3 performs a control for power generation amount adjustment, which limits the power generation amount.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] For example, in a power source mounted on a vehicle, it is necessary to prevent overheating for safety. For example, Patent Document 1 discloses a technique that can suppress output when signs of overheating start to appear and prevent overheating.

[0003] In the above technique, by adding the coolant temperature as a control factor, when the coolant temperature is above a predetermined temperature, power control is performed based on the lower of the upper limit power generation amount and the target power generation amount that decreases as the coolant temperature rises. This prevents overheating and overcooling of the in-vehicle engine, prevents overcharging of the in-vehicle battery, and does not give the user an unnatural impression.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a fuel cell system equipped with a fuel cell as a power source (power supply source), since overheating of auxiliary components is conceivable, it is necessary to control the temperature by the same technique as in Patent Document 1.

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

[0007] One aspect of the present invention is to suppress the deterioration of NV (Noise, Vibration, and Harshness) due to fluctuations in the amount of power generated, and to suppress the deterioration of the 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 embodiment of the present invention is a fuel cell system comprising 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 related to the fuel cell unit, and a temperature acquisition means that acquires the temperature related to the fuel cell unit.

[0009] The control unit performs power generation adjustment control to limit the amount of power generated when the temperature obtained by the temperature acquisition means exceeds a predetermined temperature condition.

[0010] As a result, when the temperature acquired by the temperature acquisition means, which acquires the temperature related to the fuel cell unit, exceeds a predetermined temperature condition, power generation adjustment control is implemented to limit the amount of power generated. Therefore, even if the temperature related to the fuel cell unit exceeds a predetermined temperature condition, it is possible to suppress hunting of the amount of power generated. As a result, the generation of NV (noise, vibration, and noise) can be suppressed, and the deterioration of the fuel cell cells can be suppressed.

[0011] Furthermore, the limiting factor used for the power generation adjustment control may be configured to have a predetermined time before being updated as a control cycle, and the cycle for updating the power generation limiting factor for implementing the power generation adjustment control may be longer than the control cycle of the limiting factor.

[0012] This stabilizes power generation by the fuel cell unit and suppresses the degradation of the fuel cell cells. Furthermore, it reduces noise fluctuations from auxiliary equipment and improves NV characteristics.

[0013] Furthermore, the control unit may have a limiting factor map set based on temperature, and the control unit may be configured to obtain a limiting factor from the limiting factor map, calculate a final target power amount by multiplying the maximum power generation of the fuel cell unit by the limiting factor, compare the final target power amount with the power generation amount determined from the SOC of the fuel cell unit, and control the power generation amount of the fuel cell unit by the power generation amount adjustment control.

[0014] This allows the control unit to set an appropriate power generation amount because, based on the limiting factor map, the limiting factor is acquired as the auxiliary equipment temperature rises.

[0015] Furthermore, the limiting factor may be configured to decrease linearly as the temperature obtained by the temperature acquisition means increases.

[0016] As a result, based on the limiting factor map, the limiting factor decreases linearly as the auxiliary equipment temperature rises, allowing the control unit to set an appropriate power generation amount.

[0017] Furthermore, the temperature acquisition means is capable of acquiring the temperature of each of the auxiliary components, and the control unit may determine the power generation limiting rate of the fuel cell unit based on the smallest of the multiple limiting rates calculated based on the acquired temperatures of each of the auxiliary components.

[0018] As a result, the control unit can finely set an appropriate power generation amount.

[0019] Further, as the predetermined temperature condition, it has a first temperature threshold value and a second temperature threshold value, and the control unit may apply the limiting rate when exceeding the first temperature threshold value, and may make the limiting rate constant when exceeding the second temperature threshold value.

[0020] As a result, even when the auxiliary machine temperature becomes a certain level or higher, it is possible to secure a necessary power generation amount and perform an evacuation measure.

Advantages of the Invention

[0021] According to the present invention, in a fuel cell system that controls the power generation amount by controlling the operation of an auxiliary machine, it is possible to suppress deterioration of NV due to hunting of the power generation amount and suppress deterioration of the cells of the fuel cell.

Brief Description of the Drawings

[0022] [Figure 1] It is a diagram showing an example of a fuel cell system of an embodiment. [Figure 2] It is a diagram showing an example of power generation amount adjustment control implemented by a control unit. [Figure 3] It is a diagram showing an example of a limiting rate map. [Figure 4] It is a diagram showing the relationship between the control cycle in which the limiting rate is updated and the cycle in which the power generation amount limiting rate is updated. [Figure 5] It is a flowchart showing an example of a limiting rate acquisition process in the power generation amount adjustment control executed by a control unit. [Figure 6] It is a flowchart showing an example of a power generation amount calculation process in the power generation amount adjustment control executed by a control unit.

Modes for Carrying Out the Invention

[0023] Hereinafter, embodiments will be described in detail based on the drawings.

[0024] Figure 1 shows an example of a fuel cell system according to an embodiment.

[0025] The fuel cell system 1 shown in Figure 1 is installed in vehicles Ve such as industrial vehicles like forklifts or automobiles. Vehicle Ve is equipped with an external load Lo, such as an inverter that drives the traction motor, and power is supplied to the external load Lo from the fuel cell system 1.

[0026] The fuel cell system 1 comprises a fuel cell (fuel cell unit) FC, a fuel tank T, and an air compressor ACP.

[0027] Furthermore, the fuel cell system 1 also includes a radiator R, a fan F, a water pump WP, a DC-DC converter CNV, an energy 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).

[0028] The fuel cell system 1 outputs power to an external load Lo, etc., based on auxiliary equipment, which is equipment that has auxiliary functions required when the fuel cell FC generates power. Auxiliary equipment refers to equipment related to the fuel cell FC. 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, and an energy storage device B. In this embodiment, auxiliary equipment may also include the fuel cell FC itself. Auxiliary equipment may also include other equipment not shown in Figure 1.

[0029] A fuel cell (FC) is a fuel cell composed of multiple fuel cell cells 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 oxidizing gas (such as air).

[0030] Fuel tank T is a storage container for fuel gas. The fuel gas stored in fuel tank T is supplied to the fuel cell (FC).

[0031] The air compressor ACP compresses the oxidizer gas present around the fuel cell system 1 and supplies it to the fuel cell FC. The compression ratio of the air compressor ACP is controlled by adjusting the opening of a valve located downstream of the fuel cell FC.

[0032] 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.

[0033] Fan F increases the heat dissipation rate of radiator R by directing cooling air onto radiator R.

[0034] The water pump (WP) supplies the refrigerant cooled by the radiator (R) to the fuel cell (FC).

[0035] 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 to voltage Vch (e.g., 48[V]). The power output from the DC-DC converter CNV is supplied to the external load Lo, the internal load Li, and the energy storage device B. The internal load Li includes the air compressor ACP, the water pump WP, and the fan F, among others. The internal load Li may also include other equipment not shown in Figure 1.

[0036] Energy storage device B consists of lithium-ion capacitors and lithium-ion secondary batteries, and is connected between the DC-DC converter CNV and the external load Lo.

[0037] If the supplied power, which is the difference between the power output from the DC-DC converter CNV and the power supplied to the internal load Li, is greater than the required power from the external load Lo, then the power equivalent to the required power is supplied to the external load Lo, and the remaining power is supplied to the energy storage device B. When power is supplied from the DC-DC converter CNV to the energy storage device B, the energy storage device B is charged and its State of Charge (SOC) increases. Also, if the supplied power, which is the difference between the power output from the DC-DC converter CNV and the power supplied to the internal load Li, is less than the required power from the external load Lo, then the supplied power is supplied to the external load Lo, and the remaining power is supplied from the energy storage device B to the external load Lo. When power is supplied from the energy storage device B to the external load Lo, the energy storage device B is discharged and its SOC decreases. Note that SOC refers to the charge rate [%] of energy storage device B (the ratio of remaining capacity to the full charge capacity of energy storage device B), or the open-circuit voltage [V] of energy storage device B when no current is flowing through it, or the closed-circuit voltage [V] of energy storage device B when current is flowing through it, or the integrated value [Ah] of the current flowing through energy storage device B.

[0038] The current sensor Sif is composed of 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.

[0039] The voltage sensor Svf is composed of voltage divider resistors and the like, and detects the voltage Vfc of the fuel cell FC, and sends the detected voltage Vfc to the control unit 3.

[0040] 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 temperature of each auxiliary equipment related to the fuel cell system 1 (hereinafter also referred to as "auxiliary equipment temperature"). The first temperature sensor TH1, the second temperature sensor TH2, and the third temperature sensor TH3 are composed of, for example, thermistors. The first temperature sensor TH1, the second temperature sensor TH2, and the third temperature sensor TH3 each send the acquired auxiliary equipment temperature to the control unit 3.

[0041] The first temperature sensor TH1 acquires the temperature of the fuel cell FC (hereinafter also referred to as the "first auxiliary device AM1"). For example, the first temperature sensor TH1 can acquire the temperature of the fuel cell FC (hereinafter also referred to as the "first auxiliary device temperature AT1") by acquiring the temperature of the refrigerant heated by the heat generated by the fuel cell FC. The first temperature sensor TH1 sends the acquired first auxiliary device temperature AT1 to the control unit 3.

[0042] The second temperature sensor TH2 acquires the temperature of the air compressor ACP (hereinafter also referred to as "second auxiliary equipment AM2"). For example, the second temperature sensor TH2 can acquire the temperature of the air compressor ACP (hereinafter also referred to as "second auxiliary equipment temperature AT2") by measuring the temperature in the vicinity of the air compressor ACP. The second temperature sensor TH2 sends the acquired second auxiliary equipment temperature AT2 to the control unit 3.

[0043] The third temperature sensor TH3 acquires the temperature of the DC-DC converter CNV (hereinafter also referred to as "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 "third auxiliary device temperature AT3") by measuring the temperature of the MOSFET (metal-oxide-semiconductor field-effect transistor) that constitutes the DC-DC converter CNV. The third temperature sensor TH3 sends the acquired third auxiliary device temperature AT3 to the control unit 3.

[0044] The memory unit 2 is composed of RAM (Random Access Memory) and ROM (Read Only Memory), among other components. The memory unit 2 stores limit rate maps set based on the auxiliary equipment temperatures (first auxiliary equipment temperature AT1, second auxiliary equipment temperature AT2, and third auxiliary equipment temperature AT3). A limit rate map is set for each auxiliary equipment. Details of the limit rate maps will be described later.

[0045] The control unit 3 is composed of a microcomputer and the like.

[0046] Furthermore, when the fuel cell system 1 is in operation, the control unit 3 gradually changes the target power generation value TPG according to the SOC of the energy storage device B.

[0047] Furthermore, when the fuel cell system 1 is in operation, the control unit 3 controls the operation of the internal load Li so that the power generated by the fuel cell FC follows the target power generation value TPG. For example, when the fuel cell system 1 is in operation, the control unit 3 controls the operation of the internal load Li using PI (Proportional-Integral) control so that the difference between the power generated by the fuel cell FC and the target power generation value TPG becomes zero.

[0048] The control unit 3 controls the amount of electricity generated by the fuel cell FC by controlling the operation of auxiliary equipment related to the fuel cell FC. When the temperatures of each auxiliary equipment (first auxiliary equipment temperature AT1, second auxiliary equipment temperature AT2, third auxiliary equipment temperature AT3) obtained by the temperature sensors (first temperature sensor TH1, second temperature sensor TH2, third temperature sensor TH3) exceed a predetermined temperature (t1) condition, the control unit 3 performs power generation adjustment control to limit the amount of electricity generated.

[0049] Figure 2 shows an example of power generation adjustment control performed by the control unit 3. The control unit 3 has a different limiting factor map for each auxiliary device. In Figure 2, the control unit 3 has a first limiting factor map MP1, a second limiting factor map MP2, and a third limiting factor map MP3. The limiting factor maps are not limited to those shown in Figure 2. The same limiting factor map may be used for each auxiliary device.

[0050] The control unit 3 obtains the limiting ratio from the limiting ratio maps (first limiting ratio map MP1, second limiting ratio map MP2, third limiting ratio map MP3). For example, the control unit 3 determines whether or not auxiliary equipment temperatures (first auxiliary equipment temperature AT1, second auxiliary equipment temperature AT2, third auxiliary equipment temperature AT3) have been sent from the temperature sensors (first temperature sensor TH1, second temperature sensor TH2, third temperature sensor TH3) that measure the temperature of the auxiliary equipment. If auxiliary equipment temperatures have been sent from the temperature sensors, the control unit 3 obtains the sent auxiliary equipment temperatures (first auxiliary equipment temperature AT1, second auxiliary equipment temperature AT2, third auxiliary equipment temperature AT3). Then, the control unit 3 refers to the limiting ratio map corresponding to the obtained auxiliary equipment and obtains the limiting ratio of the corresponding auxiliary equipment.

[0051] Figure 3 shows an example of a limiting factor map. The limiting factor map has a first limiting factor set based on the limiting factor and the auxiliary equipment temperature. Figure 3 explains the first limiting factor map MP1 as an example of a limiting factor map. The second limiting factor map MP2 and the third limiting factor map MP3 have the same configuration as the first limiting factor map MP1, so their explanation is omitted.

[0052] In the first limit rate map MP1 of Figure 3, temperature t1 (first temperature threshold) indicates the temperature at which limiting begins due to power generation adjustment control (hereinafter also referred to as the "limiting start temperature"). Temperature t2 (second temperature threshold) indicates the maximum temperature at which limiting is permitted due to power generation adjustment control (hereinafter also referred to as the "maximum limiting temperature"). Temperature t3 (third temperature threshold) indicates the threshold temperature at which a failure of the fuel cell system 1 is confirmed (diagnosis confirmation temperature). Temperature t2 is set between temperature t3 and temperature t1. For example, temperature t2 may be set midway between temperature t3 and temperature t1.

[0053] In the first restriction rate map MP1 in Figure 3, the normal restriction rate NLR represents a state where no restriction is applied, for example, a relationship such as "normal restriction rate NLR = 1" is set. The lower restriction rate LLR represents a state where the restriction is at its maximum, for example, a relationship such as "1 > lower restriction rate LLR > 0" is set.

[0054] The control unit 3 fixes the limiting factor to the normal limiting factor NLR by referring to the limiting factor map in Figure 3 until the acquired first auxiliary temperature AT1 reaches temperature t1. In other words, there is no limiting effect until the auxiliary temperature reaches temperature t1. When the acquired first auxiliary temperature AT1 exceeds temperature t1, the control unit 3 decreases the limiting factor linearly as the acquired first auxiliary temperature AT1 rises. In other words, the control unit 3 gradually decreases the limiting factor from the normal limiting factor NLR towards LR2. Then, when the acquired first auxiliary temperature AT1 reaches temperature t2, the control unit 3 fixes the limiting factor to LR2. Based on the limiting factor map, the limiting factor decreases linearly as the auxiliary temperature rises, so the control unit 3 can set an appropriate power generation amount.

[0055] As described above, the control unit 3 is in a state where no restriction is applied until the auxiliary equipment temperature reaches temperature t1. When the auxiliary equipment temperature exceeds temperature t1, a limiting rate that decreases linearly as the auxiliary equipment temperature rises is applied, and when it exceeds temperature t2, the limiting rate is set to a constant lower limiting rate LLR. This ensures that even if the auxiliary equipment temperature exceeds a certain level, the necessary amount of power generation can be secured to some extent, and evacuation measures can be taken to move the vehicle to an evacuation location.

[0056] Based on the limit rate maps (first limit rate map MP1, second limit rate map MP2, third limit rate map MP3), each limit rate (first limit rate LR1, second limit rate LR2, third limit rate LR3) is updated. Then, the control unit 3 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 limit rate PLR. The power generation limit rate PLR ​​is a ratio used to implement power generation 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 limit rate PLR.

[0057] The control unit 3 calculates the final target energy amount FTP by multiplying the acquired limiting factors (first limiting factor LR1, second limiting factor LR2, third limiting factor LR3) by the maximum power generation amount (maximum generated power) MPG. For example, the control unit 3 calculates the final target energy amount FTP by multiplying the power generation limiting factor PLR, which is determined based on the updated limiting factors (first limiting factor LR1, second limiting factor LR2, third limiting factor LR3), by the maximum power generation amount MPG. The maximum power generation amount MPG is the maximum amount of power that can be output by the fuel cell FC. The maximum power generation amount MPG is preset to correspond to the fuel cell FC.

[0058] 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 energy storage device B, and controls the amount of power generated by the fuel cell FC through power generation adjustment control. Specifically, the control unit 3 calculates the smaller of the calculated final target power amount FTP and the power generation amount PGS determined from the SOC as the power generation target value TPG.

[0059] The power generation amount PGS, determined from the State of Charge (SOC), is determined based on the SOC of the energy storage device B and the amount of power required from the external load Lo. The control unit 3 then controls the amount of power generated by the fuel cell FC based on the calculated power generation target value TPG.

[0060] Figure 4 shows the relationship between the control cycle in which the limiting rates (first limiting rate LR1, second limiting rate LR2, third limiting rate LR3) are updated and the cycle in which the power generation limiting rate PLR ​​is updated.

[0061] When the auxiliary unit temperatures (first auxiliary unit temperature AT1, second auxiliary unit temperature AT2, third auxiliary unit temperature AT3) are sent from the temperature sensors (first temperature sensor TH1, second temperature sensor TH2, third temperature sensor TH3) that measure each auxiliary unit (first auxiliary unit AM1, second auxiliary unit AM2, third auxiliary unit AM3), the control unit 3 starts limiting the power generation amount through power generation adjustment control.

[0062] For example, at time T11, when the first auxiliary equipment temperature AT1 is received from the first temperature sensor TH1 which measures the temperature of the first auxiliary equipment AM1, the control unit 3 refers to the first limiting rate map MP1 corresponding to the first auxiliary equipment temperature AT1 and starts updating the first limiting rate LR1 of the first auxiliary equipment AM1. Subsequently, at times T12 and T13, when the first auxiliary equipment temperature AT1 is received from the first temperature sensor TH1, the control unit 3 updates the first limiting rate LR1 of the first auxiliary equipment AM1. Therefore, the control unit 3 can update the first limiting rate LR1 of the first auxiliary equipment AM1 in the first cycle CY1 (control cycle) of times T11, T12, and T13 when the first auxiliary equipment temperature AT1 is received.

[0063] Furthermore, at time T21, when the second auxiliary equipment temperature AT2 is received from the second temperature sensor TH2, which measures the temperature of the second auxiliary equipment AM2, the control unit 3 refers to the second limiting rate map MP2 corresponding to the second auxiliary equipment temperature AT2 and starts updating the second limiting rate LR2 of the second auxiliary equipment AM2. Subsequently, at time T22, when the second auxiliary equipment temperature AT2 is received from the second temperature sensor TH2, the control unit 3 updates the second limiting rate LR2 of the second auxiliary equipment AM2. Finally, at time T23, when the second auxiliary equipment 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 equipment AM2. Therefore, the control unit 3 can update the second limiting rate LR2 of the second auxiliary equipment AM2 in the second cycle CY2 (control cycle) of times T21, T22, and T23 when the second auxiliary equipment temperature AT2 is received.

[0064] Furthermore, at time T31, when the third auxiliary equipment temperature AT3 is received from the third temperature sensor TH3, which measures the temperature of the third auxiliary equipment AM3, the control unit 3 refers to the third limiting rate map MP3 corresponding to the third auxiliary equipment temperature AT3 and starts updating the third limiting rate LR3 of the third auxiliary equipment AM3. Subsequently, at times T32, T33, and T34, when the third auxiliary equipment temperature AT3 is received from the third temperature sensor TH3, the control unit 3 updates the third limiting rate LR3 of the third auxiliary equipment AM3. Therefore, the control unit 3 can update the third limiting rate LR3 of the third auxiliary equipment AM3 in the third cycle CY3 (control cycle) of times T31, T32, T33, and T34 when the third auxiliary equipment temperature AT3 is received.

[0065] The control unit 3 determines the power generation limiting rate PLR ​​based on the first limiting rate LR1, the second limiting rate LR2, and the third limiting rate LR3. The control unit 3 determines the power generation limiting rate PLR ​​based on the smallest limiting rate among the updated limiting rates. The first limiting rate LR1, the second limiting rate LR2, and the third limiting rate LR3 are initially set to "1" if the update of the limits has not been started. In other words, if the update of any of the limiting rates LR1, LR2, and LR3 has not been started, the control unit 3 determines "1" as the power generation limiting rate PLR.

[0066] Then, the control unit 3 starts determining the power generation limiting rate PLR ​​at an arbitrary time T01. This arbitrary time T01 may be the same time as when the update of any limiting rate is started (for example, time T11). Then, the control unit 3 determines the power generation limiting rate PLR ​​in the cycle CY0 until the next arbitrary time T02.

[0067] For example, let's consider the case where the first limiting factor LR1 is updated to "0.9" at time T11. At time T01 (=time T11), the control unit 3 determines the power generation limiting factor PLR based on the smallest limiting factor. In this case, at time T01, only the first limiting factor LR1 has been updated, so the second limiting factor LR2 and the third limiting factor LR3 are both "1". Therefore, the control unit 3 determines the smallest limiting factor, the first limiting factor LR1 "0.9", as the power generation limiting factor PLR.

[0068] Furthermore, at time T02 after period CY0, if the first limiting factor LR1 is "0.9", the second limiting factor LR2 is "0.8", and the first limiting factor LR1 is "1.0", the control unit 3 determines the second limiting factor LR2 "0.8", which is the smallest limiting factor, as the power generation limiting factor PLR.

[0069] As described above, since the power generation limiting factor PLR of the fuel cell FC can be determined based on the smallest limiting factor among those calculated based on the auxiliary equipment temperature, the control unit 3 can finely set an appropriate power generation amount.

[0070] Furthermore, the limiting factors (first limiting factor LR1, second limiting factor LR2, third limiting factor LR3) used for power generation adjustment control have a predetermined time interval before being updated as part of the control cycle (first cycle CY1, second cycle CY2, third cycle CY3). The cycle CY0 for determining the power generation limiting factor PLR is set to be longer than the control cycle (first cycle CY1, second cycle CY2, third cycle CY3) of the limiting factors (first limiting factor LR1, second limiting factor LR2, third limiting factor LR3) used for power generation adjustment control. This reduces noise fluctuations from auxiliary equipment and improves NV (Noise Vibration) characteristics. Fluctuations in the limiting factors of each auxiliary equipment that change moment by moment are suppressed, which helps to suppress hunting of power generation, suppresses deterioration of vibration and noise performance which makes power generation more stable, and suppresses deterioration of the fuel cell stack.

[0071] Furthermore, the limiting factors (first limiting factor LR1, second limiting factor LR2, third limiting factor LR3) used for power generation adjustment control are set to a predetermined time before being updated as a control cycle (first cycle CY1, second cycle CY2, third cycle CY3). Therefore, the control factors (first limiting factor LR1, second limiting factor LR2, third limiting factor LR3) and the control cycle used for power generation adjustment control can be arbitrarily set according to the heat capacity of each auxiliary device so that it does not hunt.

[0072] Figures 5 and 6 are flowcharts showing an example of the power generation adjustment control process performed by the control unit 3. Figure 5 is a flowchart showing an example of the limit rate acquisition process, which is part of the power generation adjustment control performed by the control unit 3. The limit rate acquisition process described in Figure 5 is performed separately and independently from the power generation calculation process described in Figure 6. The limit rate acquisition process described in Figure 5 may be performed in series with the power generation calculation process described in Figure 6.

[0073] The limit rate acquisition process, as explained in Figure 5, is started, for example, when the ignition is turned on. In the flowchart of Figure 5, first, the control unit 3 determines whether or not auxiliary equipment temperature data has been sent from the temperature sensor (step S11). In this process, the control unit 3 determines whether or not auxiliary equipment temperature data (first auxiliary equipment temperature AT1, second auxiliary equipment temperature AT2, third auxiliary equipment temperature AT3) has been sent from any of the multiple temperature sensors (first temperature sensor TH1, second temperature sensor TH2, third temperature sensor TH3).

[0074] If no auxiliary equipment temperature is received from any of the temperature sensors (Step S11: No), the control unit 3 waits for processing. If an auxiliary equipment temperature is received from any of the temperature sensors (Step S11: Yes), the control unit 3 acquires the auxiliary equipment temperature received from the temperature sensor (Step S12).

[0075] The control unit 3 updates the limit rate of the corresponding auxiliary equipment by referring to the limit rate map corresponding to the auxiliary equipment temperature acquired in step S12 (step S13). In this process, for example, when the first auxiliary equipment temperature AT1 is sent from the first temperature sensor TH1, the control unit 3 refers to the first limit rate map MP1 and updates the first limit rate LR1 as the limit rate of the fuel cell FC corresponding to the first temperature sensor TH1. The resource rate used for power generation adjustment control has a predetermined time before it is updated as a control cycle. The control cycle in which the limit rate is updated differs for each auxiliary equipment. Therefore, the control cycle in which the limit rate is updated may differ for each auxiliary equipment. Also, if the auxiliary equipment is of the same type, the control unit 3 may update the limit rate with the same control cycle. For example, the control unit 3 may update the limit rate by referring to different limit rate maps depending on the heat capacity of the auxiliary equipment. Note that the cycle for updating the power generation target value is set to be longer than the control cycle for the limit rate. This stabilizes power generation by the fuel cell FC and suppresses the degradation of the fuel cell FC cells. Furthermore, it can reduce noise fluctuations from auxiliary equipment and improve NV characteristics.

[0076] For example, if the second auxiliary equipment temperature AT2 is received from the second temperature sensor TH2, the control unit 3 refers to the second limiting rate map MP2 and updates the second limiting rate LR2 as the limiting rate for the air compressor ACP corresponding to the second temperature sensor TH2.

[0077] For example, if the third auxiliary temperature AT3 is received 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 DCDC converter CNV corresponding to the third temperature sensor TH3.

[0078] Each time auxiliary equipment temperatures (first auxiliary equipment temperature AT1, second auxiliary equipment temperature AT2, third auxiliary equipment temperature AT3) are sent from the temperature sensors (first temperature sensor TH1, second temperature sensor TH2, third temperature sensor TH3), the control unit 3 repeatedly executes the processes in steps S11 to S13 to update each limiting rate (first limiting rate LR1, second limiting rate LR2, third limiting rate LR3).

[0079] Figure 6 is a flowchart showing an example of the power generation amount calculation process, which is part of the power generation amount adjustment control performed by the control unit 3. The power generation amount calculation process described in Figure 6 is performed separately and independently from the limit rate acquisition process described in Figure 5. The power generation amount calculation process described in Figure 6 may also be performed in series with the limit rate acquisition process described in Figure 5.

[0080] In the flowchart of Figure 6, first, the control unit 3 determines the smallest limiting factor among the limiting factors updated by the control unit 3 as the power generation limiting factor PLR (step S21). For example, the control unit 3 determines the power generation limiting factor PLR based on the smallest limiting factor among the currently updated first limiting factor LR1, second limiting factor LR2, and third limiting factor LR3.

[0081] The control unit 3 calculates the final target power amount FTP by multiplying the power generation limiting factor PLR determined in step S21 by the maximum power generation amount MPG of the fuel cell FC (step S22).

[0082] The control unit 3 compares the final target power amount FTP calculated in step S22 with the power generation amount PGS determined from the State of Charge (SOC) of the energy storage device B, and calculates the smaller of the two values ​​as the power generation target value TPG (step S23). Based on the calculated (updated) power generation target value TPG, the control unit 3 can control each auxiliary device to control the amount of power generated by the fuel cell FC.

[0083] In step S21, the control unit 3 determines whether a predetermined time has elapsed since the last determination of the power generation limit rate PLR ​​(step S24). If the predetermined time has not elapsed since the last determination of the power generation limit rate PLR ​​(step S24: No), the process goes into standby mode. If the predetermined time has elapsed since the last determination of the power generation limit rate PLR ​​(step S24: Yes), the process returns to step S21, and steps S21 to S24 are repeatedly executed. In other words, the power generation limit rate PLR ​​is continuously updated at predetermined time intervals.

[0084] It should be noted that the present invention is not limited to the embodiments described above, and various improvements and modifications are possible without departing from the spirit of the invention.

[0085] <Example 1> Figure 1 shows only three temperature sensors (first temperature sensor TH1, second temperature sensor TH2, and third temperature sensor TH3), but this is not limited to these; at least one temperature sensor is sufficient. The first temperature sensor TH1, the second temperature sensor TH2, and the third temperature sensor TH3 may acquire the temperature of the fuel cell FC, and the limiting factor for each auxiliary device may be calculated based on that temperature.

[0086] <Modification 2> In the above embodiment, the fuel cell system 1 is configured as a generator that supplies power to an external load Lo mounted on a vehicle Ve. However, the fuel cell system 1 may also be configured as a stationary generator that works in cooperation with a commercial power source to supply power to an external load Lo located outside the fuel cell system 1.

[0087] <Variation 3> In the above embodiment, the control unit 3 of the fuel cell system 1 linearly decreases the power generation limit as the acquired auxiliary equipment temperature rises when the acquired auxiliary equipment temperature exceeds temperature t1. However, the power generation limit rate may be set in steps 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 equipment temperature rises. This allows for securing a certain amount of power generation while suppressing the possibility of overheating of the fuel cell system 1 and its auxiliary equipment. [Explanation of symbols]

[0088] 1: Fuel cell system 2: Storage section 3: Control Unit ACP: Air Compressor AM1: First auxiliary engine AM2: Second auxiliary engine AM3: Third Auxiliary Unit AT1: First auxiliary temperature AT2: Second auxiliary temperature AT3: Third auxiliary equipment temperature B:Power storage device CL: Charge amount 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 LR: Normal limit rate LR1: First limit rate LR2: Second limit rate LR3: Third limit rate Li: Internal load Lo: External load MP1: First Limit Rate Map MP2: Second Limit Rate Map MP3: Third Limit Rate Map MPG: Maximum Power Generation NLR: Normal limit rate PGS: Power generation PLR: Power generation limiting 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 Value Vch: Voltage Ve: Vehicle Vfc: Voltage WP: Water pump

Claims

1. Fuel cell unit, A control unit controls the amount of electricity generated by the fuel cell unit by controlling the operation of auxiliary equipment related to the fuel cell unit, The system includes a temperature acquisition means for acquiring the temperature related to the fuel cell unit, The control unit performs power generation adjustment control to limit the amount of power generated when the temperature obtained by the temperature acquisition means exceeds a predetermined temperature condition. The limiting factor used in the aforementioned power generation adjustment control has a predetermined time interval before it is updated as a control cycle, and the cycle for updating the power generation limiting factor for implementing the power generation adjustment control is longer than the control cycle of the limiting factor. A fuel cell system characterized by the following features.

2. The control unit has a limiting factor map set based on temperature, The control unit obtains the limiting factor from the limiting factor map, calculates the final target power amount by multiplying the maximum power generation of the fuel cell unit by the limiting factor, compares the final target power amount with the power generation amount determined from the SOC of the fuel cell unit, and controls the power generation amount of the fuel cell unit by the power generation amount adjustment control. The fuel cell system according to claim 1, characterized in that it is as follows.

3. The limiting factor decreases linearly as the temperature obtained by the temperature acquisition means increases. The fuel cell system according to claim 2.

4. The temperature acquisition means is capable of acquiring the temperature of each of the auxiliary devices. The control unit determines the power generation limiting ratio of the fuel cell unit based on the smallest of the multiple limiting ratios calculated based on the acquired temperatures of each of the auxiliary devices. A fuel cell system according to any one of claims 1 to 3.

5. The predetermined temperature conditions include a first temperature threshold and a second temperature threshold. The control unit applies the limiting factor when the first temperature threshold is exceeded, and sets the limiting factor to a constant value when the second temperature threshold is exceeded. A fuel cell system according to any one of claims 1 to 3.

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