Method and computer program product for controlling a fuel cell system

Abstract

The present disclosure presents a method and a computer program product for controlling a fuel cell system. The fuel cell system is configured to supply power to an external load and comprises a galvanic pile, and a power module and a discharge resistor connected with the galvanic pile through a circuit, the power module is configured to transmit electric energy from the galvanic pile to the external load, and the method is configured to be executed after emergency shutdown of the fuel cell system. The method comprises the following steps: S100, detecting a power module to determine whether the power module has a fault; s200, if the power module breaks down, the step S300 is executed; otherwise, executing the step S400; s300, forbidding the galvanic pile to supply power to the power module, and enabling the galvanic pile to supply power to the discharge resistor until the galvanic pile voltage vstk of the galvanic pile is reduced to be below a preset voltage threshold value vthr; and S400, forbidding the galvanic pile to supply power to the discharge resistor, and enabling the galvanic pile to supply power to the power module until the galvanic pile voltage vstk of the galvanic pile is reduced to be below a preset voltage threshold value vthr.

Description

Technical Field

[0001] This disclosure relates to the field of fuel cell technology, and more specifically, to a method and computer program product for controlling a fuel cell system. Background Technology

[0002] Fuel cells have become one of the main power generation technologies due to their high power generation efficiency, low environmental pollution, and high specific energy. As a typical fuel cell, the proton exchange membrane fuel cell (PEMFC) is a popular type of fuel cell used in vehicles. A PEMFC generally consists of a solid polymer electrolyte proton-conducting membrane, such as a perfluorosulfonic acid membrane. The anode and cathode typically comprise finely divided catalyst particles, usually platinum (Pt), supported on carbon particles and mixed with ionomers. The catalyst mixture is deposited on opposite sides of the membrane. The combination of the anode catalyst mixture, the cathode catalyst mixture, and the membrane defines the membrane electrode assembly (MEA).

[0003] A fuel cell stack includes a series of bipolar plates positioned between several MEAs (Mechanical Absorbers) within the stack, with the bipolar plates and MEAs positioned between two end plates. Each bipolar plate includes an anode side and a cathode side for adjacent fuel cells within the stack. An anode gas flow channel is provided on the anode side of the bipolar plate, allowing anode reactant gas to flow to the corresponding MEA. A cathode gas flow channel is provided on the cathode side of the bipolar plate, allowing cathode reactant gas to flow to the corresponding MEA. One end plate includes an anode gas flow channel, and the other end plate includes a cathode gas flow channel. The bipolar plates and end plates are made of a conductive material such as stainless steel or a conductive composite.

[0004] When the fuel cell system in a vehicle is in normal operating mode, such as during normal vehicle operation, the electricity generated by the fuel cell is conducted to the outside of the stack via the endplates. It is then delivered to the power transmission unit by the stack's main contactor, and finally supplied to the system load, such as the vehicle's traction motor, to power the vehicle. However, when the fuel cell system shuts down in an emergency, such as during a collision or hydrogen tank leak, the stack can still generate residual electricity from the remaining reactants. If this residual electricity remains in the stack, it can cause an increase in stack voltage, potentially leading to reduced stack lifespan. In existing technologies, the residual electricity is often directed to a discharge resistor, where it is dissipated by heat. This leads to problems such as overheating and damage to the discharge resistor due to frequent use, and a shortened lifespan.

[0005] Therefore, there is an urgent need in this field for a technical solution that can quickly release the remaining charge of the fuel cell stack while also reducing the frequency of use of the discharge resistor. Summary of the Invention

[0006] To address the problems in the prior art, this disclosure proposes an improved method for controlling a fuel cell system configured to supply power to an external load, comprising a fuel cell stack, a power module and a discharge resistor connected to the fuel cell stack via circuitry, the power module being configured to deliver electrical energy from the fuel cell stack to the external load, wherein the method is configured to be executed after an emergency shutdown of the fuel cell system and includes the following steps:

[0007] S100: Detect the power module to determine if the power module has malfunctioned;

[0008] S200: If the power module fails, proceed to step S300; if the power module does not fail, proceed to step S400.

[0009] S300: Disallow the fuel cell stack from supplying power to the power module, and allow the fuel cell stack to supply power to the discharge resistor until the fuel cell stack voltage v is reached. stk Reduced to the predetermined voltage threshold v thr The following; and

[0010] S400: Disallow the fuel cell stack from supplying power to the discharge resistor, and allow the fuel cell stack to supply power to the power module until the fuel cell stack voltage v reaches its maximum value. stk Reduced to the predetermined voltage threshold v thr the following.

[0011] Similarly, in order to address the problems in the prior art described above, this disclosure also proposes a computer program product comprising a computer program, wherein the computer program is configured to cause the processor to perform the steps of the method described in this disclosure when executed by a processor.

[0012] This disclosure may be embodied in the illustrative embodiments shown in the accompanying drawings. However, it should be noted that the drawings are merely illustrative, and any variations contemplated under the teachings of this disclosure should be considered to be included within the scope of this disclosure. Attached Figure Description

[0013] The accompanying drawings illustrate exemplary embodiments of this disclosure. These drawings should not be construed as necessarily limiting the scope of this disclosure, wherein:

[0014] Figure 1 This is a schematic block diagram of a fuel cell system suitable for control by the method for controlling a fuel cell system according to the present disclosure;

[0015] Figure 2 This is a schematic flowchart of a method for controlling a fuel cell system according to one embodiment of the present disclosure;

[0016] Figure 3 This is a schematic flowchart of a method for controlling a fuel cell system according to another embodiment of the present disclosure;

[0017] Figure 4 This is a schematic flowchart of a method for controlling a fuel cell system according to another embodiment of the present disclosure; and

[0018] Figure 5 This is a schematic flowchart of a method for controlling a fuel cell system according to another embodiment of the present disclosure. Detailed Implementation

[0019] Further features and advantages of this disclosure will become more apparent from the following description with reference to the accompanying drawings. Exemplary embodiments of this disclosure are shown in the drawings, and the drawings are not necessarily drawn to scale. However, this disclosure can be implemented in many different forms and should not be construed as necessarily limited to the exemplary embodiments shown herein. Rather, these exemplary embodiments are provided merely to illustrate this disclosure and to convey the spirit and essence of this disclosure to those skilled in the art.

[0020] This disclosure aims to propose an improved method for controlling a fuel cell system. This method, in the event of an emergency shutdown of the fuel cell system, flexibly selects to release the remaining charge of the fuel cell either through the power module of the power transmission unit or through a discharge resistor, depending on the state of the power module. Therefore, compared to existing technologies that rely solely on the discharge resistor for active discharge of the fuel cell, the control method of this disclosure not only rapidly consumes the remaining charge of the fuel cell but also significantly reduces the frequency of discharge resistor usage. This reduces the risk of overheating and extends the lifespan of the discharge resistor, while also meeting the requirements for multiple discharges of the fuel cell. Therefore, compared to existing technologies, the control method of this disclosure significantly improves the stability and safety of the fuel cell system.

[0021] Various optional but non-limiting embodiments of the control method for a fuel cell system according to the present disclosure are described in detail below with reference to the accompanying drawings. However, it should be noted in advance that although the control method according to the present disclosure is described below as an example of a fuel cell system used as a power source for an electric vehicle, those skilled in the art will understand that the control method according to the present disclosure can also be used to control fuel cell systems applied in other contexts (e.g., other vehicles such as airplanes and ships, energy production devices such as water electrolysis systems, etc.). Therefore, the application context of the fuel cell system should not constitute a limitation on the scope of protection of this disclosure.

[0022] refer to Figure 1A schematic block diagram of a fuel cell system suitable for control by a method for controlling a fuel cell system according to the present disclosure is shown. Figure 1 As shown, the fuel cell system 100 is used as a power source for the electric vehicle 10 and generally includes a fuel cell 110, a power transmission unit 120, and a control unit 130. The fuel cell 110 generates electrical energy through an electrochemical reaction of a cathode gas (e.g., air or other oxygen-containing gas) and an anode gas (e.g., hydrogen or other hydrogen-containing gas). The power transmission unit 120 transmits the electrical energy generated by the fuel cell 110 to the high-voltage circuit 200 of the electric vehicle 10, so that the high-voltage circuit 200 serves as an external load for the fuel cell system 100 and can supply power to other loads on the electric vehicle 10. The control unit 130 controls the operation of the fuel cell 110 and the power transmission unit 120. It is worth noting that the fuel cell system 100 does not necessarily include the control unit 130, as the control unit 130 can be replaced by the electronic control unit (ECU) of the electric vehicle 10 or its fuel cell control module. In this case, the fuel cell system 100 is directly controlled by the electronic control unit of the electric vehicle 10, without necessarily including the control unit 130.

[0023] Specifically, such as Figure 1 As shown, the fuel cell 110 includes a stack 111 and auxiliary devices such as a compressor 112 and an injector 113. Under the control of a control unit 130, the compressor 112 compresses air from the atmosphere and delivers it to the stack 111 as cathode gas for the electrochemical reaction, while the injector 113 delivers hydrogen from a hydrogen storage tank 114 to the stack 111 as anode gas for the electrochemical reaction. The anode and cathode gases delivered to the stack 111 spontaneously undergo an electrochemical reaction at the proton exchange membrane (PEM) in the stack 111, thereby generating electrical energy. Afterward, the cathode gas is discharged from the stack 111 and subsequently released into the atmosphere, while the anode gas is also discharged from the stack 111 and, after dilution, released into the atmosphere or returned to the stack 111 via an anode gas recirculation line (not shown) to participate in subsequent electrochemical reactions.

[0024] like Figure 1As shown, the power transmission unit 120 includes a power module 121 and a discharge resistor 122. The power module 121 is electrically connected to the main contactors 111a and 111b of the fuel cell stack 111 via a power supply circuit L1. The discharge resistor 122 is electrically connected to the main contactors 111a and 111b of the fuel cell stack 111 via a discharge circuit L2. The power supply circuit L1 and the discharge circuit L2 connect the power module 121 and the discharge resistor 122 in parallel. Additionally, the power module 121 is also electrically connected to a high-voltage circuit 200, enabling it to transmit the electrical energy generated by the fuel cell stack 111 to the high-voltage circuit 200.

[0025] Typically, during normal operation of the electric vehicle 10, the fuel cell system 100 operates normally and the high-voltage circuit 200 has a power demand. At this time, the power module 121 needs to adjust the electrical energy generated by the fuel cell stack 111 and deliver it to the high-voltage circuit 200 to meet its power demand. To this end, the control unit 130 conducts (e.g., by closing the power switch S1 on the power supply circuit L1) the electrical connection between the fuel cell stack 111 and the power module 121 and places the power module 121 in a normal current control mode, so that the power module 121 provides the required power to the high-voltage circuit 200. In other words, the normal current control mode is the mode in which the power module 121 operates when the fuel cell system 100 is operating normally. In this normal current control mode, the power module 121 can adjust the power supply according to the real-time detected stack voltage v of the fuel cell stack 111. stk , stack current i stk The system provides the required power to the high-voltage circuit 200 based on parameters such as power requests, and can also perform undervoltage and overvoltage protection. Specifically, it controls the power supply to the high-voltage circuit 200 based on parameters such as power requests. stk Below the predetermined lower voltage limit v stk-l and above the predetermined voltage upper limit v stk-h When this occurs, the power transmission unit 120 disconnects the electrical connection between the fuel cell stack 111 and the power module 121 to prevent the fuel cell stack 111 from supplying power to the power module 121, thereby preventing damage to the load on the high-voltage circuit 200 caused by excessively low or high voltage.

[0026] Furthermore, when the electric vehicle 10 is shut down, the fuel cell system 100 shuts down and the high-voltage circuit 200 has no power demand. However, the fuel cell stack 111 still generates some electrical energy (referred to herein as residual electrical energy or residual charge). This is because although the compressor 112 and injector 113 stop supplying cathode and anode gas to the fuel cell stack 111, the remaining cathode and anode gas in the stack 111 and pipelines still undergo electrochemical reactions. At this time, the discharge resistor 122 needs to consume the residual charge in the fuel cell stack 111 to prevent this residual charge from remaining in the stack 111, thereby affecting the service life of the fuel cell stack 111 or even causing damage to the fuel cell stack 111 and triggering some safety issues. To this end, the control unit 130 will conduct (e.g., by closing the discharge switch S2 on the discharge circuit L2) the electrical connection between the fuel cell stack 111 and the discharge resistor 122, so that current flows through the discharge resistor 122, and the discharge resistor 122 will convert electrical energy into heat energy through heating, thereby consuming the residual charge in the fuel cell stack 111.

[0027] like Figure 1 As shown, the high-voltage circuit 200 typically includes a DC / DC boost converter 210, a vehicle traction motor 220, a DC / AC converter 230, a high-voltage battery 240, and other devices. The DC / DC boost converter 210 is electrically connected to the power module 121 and is configured to boost the low voltage level supplied by the power module 121 to a high voltage level suitable for driving the high-voltage load on the high-voltage circuit 200. For example, the voltage level required to drive the vehicle traction motor 220 is often higher than the voltage level that the power module 121 can output; therefore, the DC / DC boost converter 210 is needed to boost the voltage level from the power module 121. The DC / AC converter 230 is electrically connected to the DC / DC boost converter 210 and is configured to convert the DC power supplied by the DC / DC boost converter 210 into AC power suitable for supplying to the phase windings of the vehicle traction motor 220 to drive the vehicle traction motor 220. A high-voltage battery 240 is electrically connected to a DC / DC boost converter 210 and configured to store electrical energy supplied by the DC / DC boost converter 210 and to supply electrical energy to other high-voltage loads on the high-voltage circuit 200. Specifically, a DC / DC (direct current / direct current) buck converter 310 is also electrically connected to the DC / DC boost converter 210 and configured to convert the high voltage level provided by the DC / DC boost converter 210 to a low voltage level for driving low-voltage loads (e.g., car audio, car air conditioning, etc.) on the electric vehicle 10.

[0028] In short, according to Figure 1The fuel cell system 100 shown is configured such that, when the fuel cell system 100 is operating normally, the electrical energy generated by the fuel cell 110 can be supplied to the high-voltage circuit 200 through the power module 121 to drive various loads on the electric vehicle 10. When the fuel cell system 100 shuts down, the remaining electrical energy of the fuel cell 110 can be converted into heat energy by the discharge resistor 122 and released therefrom. However, when events such as hydrogen leakage, fuel cell system overload, or electric vehicle collision cause the fuel cell system 100 to shut down urgently, if the discharge resistor 122 consumes the remaining electrical energy of the fuel cell 110 in every emergency shutdown, the discharge resistor 122 may have its service life shortened or even overheated and damaged due to frequent heating, which could adversely affect the safety and reliability of the entire fuel cell system 100.

[0029] In order to reduce the frequency of use of the discharge resistor 122 in order to improve the safety and reliability of the fuel cell system 100, this disclosure proposes a method for controlling the fuel cell system 100, which is configured to be executed by the control unit 130 (or, in the case where the fuel cell system 100 does not include the control unit 130, by the electronic control unit of the electric vehicle 10 or its fuel cell control module) after an emergency shutdown of the fuel cell system 100, so as to release the remaining electrical energy in the stack 111 after the emergency shutdown of the fuel cell system 100.

[0030] refer to Figure 2 The diagram illustrates a schematic flowchart of a method for controlling a fuel cell system according to one embodiment of the present disclosure. Figure 2 As shown, the control method includes the following steps:

[0031] S100: Detect power module 121 to determine if power module 121 has malfunctioned. For example, control unit 130 can run a test program for power module 121 after an emergency shutdown of fuel cell system 100, and determine whether power module 121 has malfunctioned based on the results of the test program.

[0032] S200: If the power module 121 fails, proceed to step S300; if the power module 121 does not fail, proceed to step S400.

[0033] S300: Disconnect the power supply switch S1 to prevent the fuel cell stack 111 from supplying power to the power module 121, and close the discharge switch S2 to allow the fuel cell stack 111 to supply power to the discharge resistor 122 until the fuel cell stack voltage v of the fuel cell stack 111 reaches zero. stk Reduced to the predetermined voltage threshold v thr the following.

[0034] S400: Disconnect discharge switch S2 to prevent fuel cell stack 111 from supplying power to discharge resistor 122, and close power supply switch S1 to allow fuel cell stack 111 to supply power to power module 121 until the fuel cell stack voltage v of fuel cell stack 111 reaches zero. stk Reduced to the predetermined voltage threshold v thr the following.

[0035] It is worth mentioning that the stack voltage v mentioned in steps S300 and S400 stk This could be the stack voltage on the main contactors 111a and 111b of the fuel cell stack 111, detected by a voltage sensor (not shown), the single-cell voltage of a particular cell in the fuel cell stack 111, or the average value of the single-cell voltages of all or some of the cells, etc., while a predetermined voltage threshold v thr It can be set according to prior experiments conducted on fuel cell 111 or operator experience, such that if the fuel cell voltage v stk At the predetermined voltage threshold v thr Therefore, the remaining electrical energy in the fuel cell stack 111 is insufficient to cause damage to the fuel cell stack 111. Thus, those skilled in the art will understand that the predetermined voltage threshold v is limited by factors such as the type, configuration, and application of the fuel cell stack 111. thr There will be differences. Specifically, the predetermined voltage threshold v thr It can be set to a voltage lower than the predetermined lower limit v in the above normal current control mode. stk-l So that the above-mentioned active discharge can reduce the stack voltage v stk Reduced to the lower voltage limit v stk-l The following, instead of the normal current control mode where the stack voltage v stk Reduced to the lower voltage limit v stk-l The undervoltage protection will now be implemented.

[0036] Based on the descriptions of the above steps, if a fault is determined in step S200 for power module 121, then in step S300, power supply from fuel cell stack 111 to power module 121 is prohibited to avoid system damage caused by powering the faulty power module 121. Instead, power is supplied from fuel cell stack 111 to discharge resistor 122, thereby enabling active discharge of fuel cell stack 111 through discharge resistor 122 until the fuel cell stack voltage v reaches zero. stk Reduced to the predetermined voltage threshold v thrThe following applies. During this period, the remaining electrical energy of the fuel cell stack 111 will be supplied to the discharge resistor 122 and converted into heat energy by the discharge resistor 122. That is, the discharge resistor 122 will consume the remaining electrical energy of the fuel cell stack 111 by heating up, so as to prevent the fuel cell stack 111 from being damaged by the remaining electrical energy trapped inside. Specifically, in step S300, the control unit 130 can generate a discharge command after determining that the power module 121 has failed, and then send the discharge command to the power transmission unit 120. The power transmission unit 120 can disconnect the power supply switch S1 and close the discharge switch S2 after receiving the discharge command, thereby selecting the discharge resistor 122 instead of the power module 121 to actively discharge the fuel cell stack 111.

[0037] However, if it is determined in step S200 that the power module 121 has not malfunctioned, then in step S400, the power supply from the fuel cell stack 111 to the discharge resistor 122 is prohibited, and the fuel cell stack 111 is allowed to supply power to the power module 121, thereby enabling the power module 121 to actively discharge the fuel cell stack 111 until the fuel cell stack voltage v of the fuel cell stack 111 reaches zero. stk Reduced to the predetermined voltage threshold v thr The following applies. During this period, the remaining electrical energy of the fuel cell stack 111 will be supplied to the power module 121. The power module 121 can, for example, pulse-width modulate the electrical energy supplied by the fuel cell stack 111 and then supply it to the high-voltage circuit 200 of the electric vehicle 10. This consumes the remaining electrical energy of the fuel cell stack 111 by supplying power to the high-voltage circuit 200 through the power module 121, thereby preventing damage to the fuel cell stack 111 due to residual electrical energy remaining inside. Specifically, in step S400, the control unit 130 can generate a power supply command after determining that the power module 121 has not malfunctioned, and then send the power supply command to the power transmission unit 120. Upon receiving the power supply command, the power transmission unit 120 can close the power supply switch S1 and open the discharge switch S2, thereby selecting the power module 121 instead of the discharge resistor 122 to actively discharge the fuel cell stack 111.

[0038] As described above, by using the control method of this disclosure, after an emergency shutdown of the fuel cell system 100, the power module 121 is preferentially used to release the remaining electrical energy in the stack 111, and the discharge resistor 122 is only used to release the remaining electrical energy in the stack 111 in the event of a failure of the power module 121. This not only allows for rapid release of the remaining electrical energy in the stack 111 after an emergency shutdown of the fuel cell system 100, but also significantly reduces the frequency of use of the discharge resistor 122, thereby preventing the discharge resistor 122 from having a shortened lifespan or even overheating damage due to frequent use. Therefore, the control method of this disclosure can significantly improve the reliability and safety of the fuel cell system 100 while achieving rapid discharge of the stack 111.

[0039] In particular, such as Figure 2 As shown, the control method may further include step S500 after steps S300 and S400: disconnecting the power supply switch S1 and the discharge switch S2 to prevent the fuel cell stack 111 from supplying power to either the power module 121 or the discharge resistor 122. Based on the descriptions of steps S300, S400, and S500, whether the fuel cell stack 111 is actively discharged through the discharge resistor 122 in step S300 or actively discharged through the power module 121 in step S400, the fuel cell stack voltage v will remain constant. stk Reduced to the predetermined voltage threshold v thr The following step, S500, is executed to prevent the fuel cell stack 111 from supplying power to either the power module 121 or the discharge resistor 122, thereby ending the active discharge through either the power module 121 or the discharge resistor 122. Specifically, in step S500, the control unit 130 can generate a power-off command and send it to the power transmission unit 120. Upon receiving the power-off command, the power transmission unit 120 can disconnect the power supply switch S1 and the discharge switch S2, thereby disconnecting the electrical connection between the fuel cell stack 111 and the power module 121 and the discharge resistor 122.

[0040] refer to Figure 3 The diagram shows a schematic flowchart of a method for controlling a fuel cell system according to another embodiment of the present disclosure. Figure 3 The embodiments shown are the same as Figure 2 The difference in the illustrated implementation is that step S400 includes the following sub-steps:

[0041] S410: Close the power supply switch S1 to allow the fuel cell stack 111 to supply power to the power module 121, and open the discharge switch S2 to prevent the fuel cell stack 111 from supplying power to the discharge resistor 122, thereby enabling the fuel cell stack 111 to actively discharge through the power module 121.

[0042] S420: Detects the stack voltage v of fuel cell stack 111. stk and the detected stack voltage v stk With the predetermined voltage threshold v thr Compare them.

[0043] S430: If the stack voltage v stk At the predetermined voltage threshold v thr Below, i.e., v stk ≤v thr If the stack voltage v stk At the predetermined voltage threshold v thr Above, that is, v stk >v thrThen, sub-step S440 is executed. Combining the descriptions of sub-steps S430 and S500, it can be seen that if the stack voltage v is determined in sub-step S430... stj At the predetermined voltage threshold v thr This means that the active discharge performed by the power module 121 has released the remaining electrical energy in the fuel cell stack 111 to a level that is insufficient to damage the fuel cell stack 111. In other words, the active discharge of the fuel cell stack 111 has been completed, so the active discharge of the fuel cell stack 111 ends in step S500.

[0044] S440: Determine the duration t of the active discharge of fuel cell stack 111. ad and the determined duration t ad With the predetermined time threshold t thr (Also known as the first predetermined time threshold) is compared. Combining the descriptions of sub-steps S430 and S440, it can be seen that if the stack voltage v is determined in sub-step S430... stk At the predetermined voltage threshold v thr This indicates that the remaining electrical energy in fuel cell 111 is still sufficient to damage it, meaning that the active discharge of fuel cell 111 has not yet been completed. Therefore, in sub-step S440, the duration t of the active discharge is set. ad With the predetermined time threshold t thr A comparison is made to determine whether the active discharge performed by power module 121 has lasted for a sufficiently long time. It is worth noting that this is compared with a predetermined voltage threshold v. thr Similarly, the predetermined time threshold t thr It can also be set based on prior experiments conducted on fuel cell stack 111 or the experience of operators, and therefore will vary depending on factors such as the type, configuration, and application of fuel cell stack 111.

[0045] S450: If the duration t ad Exceeding the predetermined time threshold t thr That is, t ad ≥t thr If the duration t ad The predetermined time threshold t has not been exceeded. thr That is, t ad <t thr Then return to sub-step S410. Combining the descriptions of sub-steps S430, S440, S450, and step S500, it can be seen that if the duration t is determined in sub-step S450... ad The predetermined time threshold t has not been exceeded. thrThis indicates that the active discharge via power module 121 has not lasted long enough, therefore the process returns to sub-step S410 to continue the active discharge of the fuel cell stack 111 via power module 121. Conversely, if the duration t is determined in sub-step S450... ad Exceeding the predetermined time threshold t thr This indicates that the active discharge via power module 121 has lasted for a sufficiently long time, but the stack voltage v stk However, it still did not decrease to the predetermined voltage threshold v. thr Therefore, it can be assumed that the active discharge of the fuel cell stack 111 has failed, and thus the active discharge via the power module 121 is terminated in step S500. This configuration is advantageous because the inability of the fuel cell stack 111 to complete the discharge via the power module 121 within a specified time may indicate that the power supply circuit L1, the power module 121, the high-voltage circuit 200, or other components have been damaged. In this case, timely cessation of the active discharge of the fuel cell stack 111 can prevent further damage to the fuel cell system 100.

[0046] Specifically, in sub-step S410, the control unit 130 can also place the power module 121 in a discharge current control mode, in which the power module 121 can adjust the discharge current control mode according to the stack voltage v of the fuel cell stack 111. stk and the predetermined voltage and current curve c v-i To control the stack current i of fuel cell stack 111 stk .

[0047] Specifically, the voltage-current curve c above v-i The calibration is performed based on the actual fuel cell stack 111 used, so that each fuel cell stack 111 has a specific voltage-current curve c. v-i Specifically, in the aforementioned voltage-current curve c v-i In the middle, the stack current i stk With the stack voltage v stk There is a positive correlation, that is, the stack voltage v stk The larger the value, the higher the stack current i. stk The larger the value, the lower the value; conversely, the smaller the value, the lower the stack voltage v. stk The smaller the value, the lower the stack current i. stk The smaller the value, the better. This configuration is advantageous because if the stack voltage v... stk A larger current i indicates that there is more residual electrical energy in fuel cell 111. In this case, a larger fuel cell current i can be used. stk To accelerate the release of this surplus electrical energy; conversely, if the stack voltage v stk A smaller value indicates that there is less remaining electrical energy in the fuel cell stack 111. In this case, a smaller fuel cell current i can be used. stkThis slows down the release of the remaining electrical energy, ensuring that regardless of the amount of remaining electrical energy in the fuel cell stack 111, the discharge can be completed within a relatively consistent discharge time, without the phenomenon of a significant increase in discharge time due to the increase in remaining electrical energy. This not only helps protect the fuel cell stack 111, but also allows for a more consistent duration of active discharge t in sub-steps S440 and S450. ad The judgment is more reasonable. Conversely, if the discharge time is significantly prolonged due to the increase in remaining electrical energy, then when there is a lot of remaining electrical energy in the fuel cell stack 111, it may lead to a misjudgment of active discharge failure in sub-steps S440 and S450.

[0048] Specifically, in sub-step S450, if the duration t ad Exceeding the predetermined time threshold t thr In addition to executing step S500, an error code can also be generated (e.g., by control unit 130) to alert the user that the active discharge of the fuel cell stack 111 has failed.

[0049] refer to Figure 4 The diagram shows a schematic flowchart of a method for controlling a fuel cell system according to another embodiment of the present disclosure. Figure 4 The embodiments shown are the same as Figure 3 The difference in the illustrated implementation is that step S300 includes the following sub-steps:

[0050] S310: Disconnect the power supply switch S1 to prevent the fuel cell stack 111 from supplying power to the power module 121.

[0051] S320: Close the discharge switch S2 to allow the fuel cell stack 111 to supply power to the discharge resistor 122, thereby enabling the fuel cell stack 111 to actively discharge through the discharge resistor 122.

[0052] S330: Detects the stack voltage v of fuel cell stack 111. stk and the detected stack voltage v stk With the predetermined voltage threshold v thr Compare them.

[0053] S340: If the stack voltage v stk At the predetermined voltage threshold v thr Below, i.e., v stk ≤v thr If the stack voltage v stk At the predetermined voltage threshold v thr Above, that is, v stk >v thr Then, sub-step S350 is executed. Combining the descriptions of sub-steps S340 and S500, it can be seen that if the stack voltage v is determined in sub-step S340... stjAt the predetermined voltage threshold v thr This means that the active discharge through the discharge resistor 122 has released the remaining electrical energy in the fuel cell stack 111 to a level that is insufficient to damage the fuel cell stack 111. In other words, the active discharge of the fuel cell stack 111 has been completed, so the active discharge of the fuel cell stack 111 ends in step S500.

[0054] S350: Determine the duration t of the active discharge of fuel cell stack 111. ad and the determined duration t ad With the predetermined time threshold t′ thr (Also known as the second predetermined time threshold) is compared. Combining the descriptions of sub-steps S340 and S350, it can be seen that if the stack voltage v is determined in sub-step S340... stk At the predetermined voltage threshold v thr This indicates that the remaining electrical energy in fuel cell 111 is still sufficient to damage it, meaning that the active discharge of fuel cell 111 has not yet been completed. Therefore, in sub-step S350, the duration t of the active discharge is set. ad With the predetermined time threshold t′ thr A comparison is made to determine whether the active discharge through discharge resistor 122 has lasted for a sufficient period of time. It should be noted that the discharge rate of the active discharge through power module 121 may differ from the discharge rate of the active discharge through discharge resistor 122; therefore, the predetermined time threshold t′ in substep S350... thr With the predetermined time threshold t in sub-step S440 thr They can be different. Of course, this is different from the predetermined time threshold t. thr Similarly, the predetermined time threshold t′ thr It can also be set based on prior experiments conducted on fuel cell stack 111 or the experience of operators, and therefore will vary depending on factors such as the type, configuration, and application of fuel cell stack 111.

[0055] S360: If the duration t ad Exceeding the predetermined time threshold t′ thr That is, t ad ≥t′ thr If the duration t ad The predetermined time threshold t′ has not been exceeded. thr That is, t ad <t′ thr Then return to sub-step S320. Combining the descriptions of sub-steps S340, S350, S360, and step S500, it can be seen that if the duration t is determined in sub-step S360... ad The predetermined time threshold t′ has not been exceeded. thrThis indicates that the active discharge through discharge resistor 122 has not lasted long enough, therefore the process returns to sub-step S320 to continue the active discharge of the fuel cell stack 111 through discharge resistor 122. Conversely, if the duration t is determined in sub-step S360... ad Exceeding the predetermined time threshold t′ thr This indicates that the active discharge through discharge resistor 122 has lasted for a sufficiently long time, but the stack voltage v stk However, it still did not decrease to the predetermined voltage threshold v. thr Therefore, it can be assumed that the active discharge of the fuel cell stack 111 has failed, and thus the active discharge through the discharge resistor 122 is terminated in step S500. This configuration is advantageous because the inability of the fuel cell stack 111 to complete the discharge through the discharge resistor 122 within a specified time may mean that the discharge circuit L2, the discharge resistor 122, or other components have been damaged. In this case, timely cessation of the active discharge of the fuel cell stack 111 can prevent further damage to the fuel cell system 100.

[0056] Specifically, in sub-step S310, the pulse width modulation of the power module 121 can also be stopped to disable the power module 121. For example, the power transmission unit 120 can stop the pulse width modulation of the power module 121 after receiving a discharge command from the control unit 130, so as to stop the operation of the power module 121.

[0057] Specifically, in sub-step S360, if the duration t ad Exceeding the predetermined time threshold t′ thr In addition to executing step S500, an error code can also be generated (e.g., by control unit 130) to alert the user that the active discharge of the fuel cell stack 111 has failed.

[0058] refer to Figure 5 The diagram shows a schematic flowchart of a method for controlling a fuel cell system according to another embodiment of the present disclosure. Figure 5 The embodiments shown are the same as Figure 4The difference in the illustrated implementation is that step S300 further includes a sub-step S311 between sub-steps S310 and S320: detecting the discharge resistor 122 to determine if the discharge resistor 122 has failed. If the discharge resistor 122 has failed, then step S500 is executed; if the discharge resistor 122 has not failed, then sub-step S320 is executed. Based on the descriptions of sub-steps S310, S320, and step S500, it can be seen that before actively discharging the fuel cell stack 111 through the discharge resistor 122, it is necessary to first determine that the discharge resistor 122 has not failed. If the discharge resistor 122 has failed, then the fuel cell stack 111 is prohibited from supplying power to the discharge resistor 122. Under this configuration, the fuel cell stack 111 can be prevented from supplying power to the failed discharge resistor 122, thereby avoiding further damage to the fuel cell system 100 caused by supplying power to the failed discharge resistor 122.

[0059] Specifically, the control unit 130 can control the fuel cell stack 111 to briefly supply power to the discharge resistor 122 and detect whether the temperature of the discharge resistor 122 rises as expected, thereby determining whether the discharge resistor 122 has failed. Of course, the control unit 130 can also determine whether the discharge resistor 122 has failed by other means (e.g., measuring the resistance, voltage, current, etc. on the discharge circuit L2).

[0060] Specifically, in sub-step S311, if the discharge resistor 122 fails, in addition to executing step S500, an error code can also be generated (e.g., by control unit 130) to alert the user that the active discharge of the fuel cell stack 111 has failed.

[0061] The foregoing has described various alternative, but non-limiting, embodiments of the control method for a fuel cell system according to this disclosure. In addition to this control method, this disclosure also aims to provide an improved computer program product for controlling a fuel cell system, the computer program product comprising a computer program configured to, when executed by a processor, cause the processor to perform the steps of the control method according to this disclosure, thereby achieving the various beneficial effects described above.

[0062] The foregoing description, with reference to the accompanying drawings, details optional but non-limiting embodiments of the method and computer program product for controlling a fuel cell system according to this disclosure. Modifications and additions to the technology and structure, as well as recombinations of features in the various embodiments, will be readily apparent to those skilled in the art without departing from the spirit and essence of this disclosure and should be considered within its scope. Therefore, such modifications and additions conceivable under the teachings of this disclosure should be considered part of this disclosure. The scope of this disclosure includes equivalent technologies known at the filing date of this disclosure and equivalent technologies not yet foreseen.

Claims

1. A method for controlling a fuel cell system (100) configured to supply power to an external load, and comprising a fuel cell stack (111) and a power module (121) and a discharge resistor (122) connected to the fuel cell stack (111) via circuitry, the power module (121) being configured to deliver electrical energy from the fuel cell stack (111) to the external load, wherein, The method is configured to be executed after an emergency shutdown of the fuel cell system (100) and includes the following steps: S100: Detect the power module (121) to determine whether the power module (121) has malfunctioned; S200: If the power module (121) fails, proceed to step S300; if the power module (121) does not fail, proceed to step S400. S300: Disallow the fuel cell stack (111) from supplying power to the power module (121), and allow the fuel cell stack (111) to supply power to the discharge resistor (122) until the fuel cell stack voltage v of the fuel cell stack (111) reaches zero. stk Reduced to the predetermined voltage threshold v thr The following; and S400: Disallow the fuel cell stack (111) from supplying power to the discharge resistor (122), and allow the fuel cell stack (111) to supply power to the power module (121) until the fuel cell stack voltage v of the fuel cell stack (111) reaches zero. stk Reduced to the predetermined voltage threshold v thr the following.

2. The method according to claim 1, wherein, When the fuel cell system (100) is operating normally, the power module (121) is in normal current control mode; and Step S400 further involves: placing the power module (121) in a discharge current control mode, wherein the discharge current control mode is different from the normal current control mode.

3. The method according to claim 2, wherein, In the normal current control mode, if the stack voltage v stk Below the predetermined lower voltage limit v stk-l If this is not the case, the fuel cell stack (111) is prohibited from supplying power to the power module (121); and Predetermined voltage threshold v thr Below the predetermined lower voltage limit v stk-l .

4. The method according to claim 2 or 3, wherein, In the discharge current control mode, the power module (121) adjusts the current according to the stack voltage v. stk and the predetermined voltage and current curve c v-i Controlling the stack current i of the fuel cell stack (111) stk .

5. The method according to claim 4, wherein, In the predetermined voltage-current curve c v-i In the middle, the stack voltage v stk With the stack current i stk They are positively correlated.

6. The method according to any one of claims 1-3, wherein, The power module (121) is configured to perform pulse width modulation on the electrical energy from the fuel cell stack (111); and Step S300 further involves stopping the pulse width modulation of the power module (121).

7. The method according to any one of claims 1-3, wherein, The method further includes step S500 after steps S300 and S400: prohibiting the fuel cell stack (111) from supplying power to either the power module (121) or the discharge resistor (122).

8. The method according to claim 7, wherein, Step S400 includes the following sub-steps: S410: Disable the fuel cell stack (111) from supplying power to the discharge resistor (122) and enable the fuel cell stack (111) to supply power to the power module (121) so that the fuel cell stack (111) can be actively discharged through the power module (121); S420: Detect the stack voltage v of the stack (111). stk and the stack voltage v stk With the predetermined voltage threshold v thr Compare; S430: If the stack voltage v stk At the predetermined voltage threshold v thr Next, step S500 is executed; if the stack voltage v stk At the predetermined voltage threshold v thr If the above is true, then sub-step S440 will be executed; S440: Determine the duration t of the active discharge. ad and the duration t ad With the first predetermined time threshold t thr Comparison; and S450: If the duration t ad Exceeding the first predetermined time threshold t thr If the duration t ad It did not exceed the first predetermined time threshold t thr If so, return to sub-step S410.

9. The method according to claim 8, wherein, Sub-step S450 also lies in: if the duration t ad Exceeding the first predetermined time threshold t thr If so, an error code will be generated.

10. The method according to claim 7 or 8, wherein, Step S300 includes the following sub-steps: S310: Prohibit the fuel cell stack (111) from supplying power to the power module (121); S320: The fuel cell stack (111) supplies power to the discharge resistor (122) so that the fuel cell stack (111) can be actively discharged through the discharge resistor (122); S330: Detect the stack voltage v of the fuel cell stack (111). stk and the stack voltage v stk With the predetermined voltage threshold v thr Compare; S340: If the stack voltage v stk At the predetermined voltage threshold v thr Next, step S500 is executed; if the stack voltage v stk At the predetermined voltage threshold v thr If the above is true, then sub-step S350 will be executed; S350: Determine the duration t of the active discharge. ad and the duration t ad With the second predetermined time threshold t t ′ hr Comparison; and S360: If the duration t ad Exceeding the second predetermined time threshold t t ′ hr If the duration t ad The second predetermined time threshold t has not been exceeded. t ′ hr If so, return to sub-step S320.

11. The method according to claim 10, wherein, Sub-step S360 also lies in: if the duration t ad Exceeding the second predetermined time threshold t′ thr If so, an error code will be generated.

12. The method according to claim 10, wherein, Second predetermined time threshold t′ thr Unlike the first predetermined time threshold t thr .

13. The method according to claim 10, wherein, Step S300 further includes a sub-step S311 between sub-steps S310 and S320: detecting the discharge resistor (122) to determine whether the discharge resistor (122) is faulty; if the discharge resistor (122) is faulty, then step S500 is executed; if the discharge resistor (122) is not faulty, then sub-step S320 is executed.

14. The method according to claim 13, wherein, Sub-step S311 further comprises: if the discharge resistor (122) fails, an error code is generated.

15. The method according to any one of claims 1-3, wherein, The external load is the high-voltage circuit (200) of the electric vehicle (10).

16. A computer program product, the computer program product comprising a computer program, wherein, The computer program is configured to cause the processor to perform the steps of the method according to any one of claims 1-15 when executed by the processor.

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