Load changing device and load changing method for fuel cell engine

Abstract

This invention provides a load-changing device for a fuel cell engine, belonging to the field of hydrogen fuel cell technology, and solves the problem of local gas shortage and inability to guarantee stable operation during load changing in existing fuel cells. The device includes: a gas flow sensor for measuring the real-time gas flow at the engine inlet; a current sensor for measuring the real-time output current of the fuel cell; and an air compression control device for determining whether a cross-condition load change has occurred after starting according to the user's load-changing command; and determining the target gas flow after the start time based on the load-changing type, controlling the air compressor to respond with an intake speed exceeding the target gas flow. Furthermore, during the above response process, the initial moment of reaching the target gas flow is identified, the output current of the fuel cell at each initial moment is acquired, and the stability of the load-changing process is determined. If unstable, a supplementary response is performed until stability is achieved, and then the gas flow is adjusted to the gas flow corresponding to the load-changing target.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen fuel cells, and in particular to a load changing device and a load changing method for a fuel cell engine. Background Art

[0002] With the application of hydrogen fuel cell technology, fuel cells are focused on high-power development. In actual application scenarios, fuel cells need to be matched with the battery of the entire vehicle, and the corresponding power response needs to be combined with the required power of the entire vehicle. In some usage scenarios, the fuel cell engine needs to change load significantly from the idle point to the rated operating point. The load change amplitude is large and the response time is short. During the load change process, the fuel, oxidant and cooling systems are required to work closely together to achieve the purpose of successful load change. However, the supply of hydrogen gas is limited by the gas diffusion rate and the response of the air supply system. There is generally a long delay effect, which will cause local gas shortage in the fuel cell, thereby affecting the performance and life of the fuel cell, which is not conducive to the stable operation of the fuel cell engine.

[0003] Under current technical conditions, fuel cell load changes will propose a pre-gas supply strategy, that is, to give priority to the supply of fuel and oxidant before the operating point to avoid local gas shortage. However, during the load change process, although the air volume can be supplied to the target volume in advance, from the measured data, the gas still has a long supply lag time due to the response of the air compressor body and the diffusion of the gas. This lag will cause local gas shortage and affect the performance and life of the fuel cell; although the gas can be supplied in advance, as the electric density point increases, its metering ratio will gradually decrease. Combined with the hysteresis effect of the gas, the air metering ratio at the target operating point will be lower than the preset metering ratio of the fuel cell engine, which will still cause local gas shortage and performance degradation. Summary of the invention

[0004] The embodiments of the present invention aim to provide a load changing device and a load changing method for a fuel cell engine, so as to solve the problem of local gas shortage and inability to ensure stable operation during the load changing process of the existing fuel cell.

[0005] On the one hand, an embodiment of the present invention provides a load variable device for a fuel cell engine, comprising:

[0006] A gas flow sensor is arranged at the air inlet of the fuel cell engine to measure the real-time gas flow at the arranged location and send it to the air compression control device;

[0007] A current sensor is provided at the output end of the fuel cell and is used to measure the real-time output current of the fuel cell and send it to the air compression control device;

[0008] An air compression control device is used to determine whether a cross-operating condition load change occurs after being started according to a user's load change instruction; and, if it occurs, determine the target gas flow rates at multiple different times after the start time according to the load change target in the load change instruction, and control the air compressor to respond at each of the different times with an intake speed exceeding the corresponding target gas flow rate; if it does not occur, identify the difference between the real-time gas flow rate and the current operating condition target gas flow rate, and control the air compressor to respond accordingly according to the difference; and, in the above-mentioned response process, identify the initial moment when the gas flow sensor measures each target gas flow rate, obtain the output current of the fuel cell at each initial moment, determine whether the load change process is stable, and if it is not stable, control the air compressor to make a supplementary response at that moment until it stabilizes and adjusts the current gas flow rate to the gas flow rate corresponding to the load change target.

[0009] The beneficial effects of the above technical solution are as follows: the existing variable load control methods are all strategies for the metering ratio required by the stack, that is, the target metering ratio of the variable load, which fail to fully consider the flow lag caused by the air diffusion effect and the response hysteresis of the air compressor, and there is a lack of flow, that is, it causes partial gas shortage, which has a huge impact on the performance and life of the stack. The above technical solution fully considers the diffusion effect of air and the response hysteresis of the air compressor, and sets the metering ratio (gas flow) during the variable load process to be higher than the target metering ratio (target gas flow) required by the stack. After the metering ratio increases, the air flow rate is increased, which can effectively slow down the gas shortage caused by gas diffusion and air compressor response hysteresis, and ensure the performance and life of the fuel cell engine.

[0010] Based on the further improvement of the above device, the load changing device further comprises an oxygen concentration sensor arranged in the air inlet pipeline of the fuel cell;

[0011] The oxygen concentration sensor is used to detect the oxygen concentration in the air in the stack pipeline in real time and send it to the air compression control device;

[0012] The air compression control device is also used to compare the received oxygen concentration with a threshold value to determine whether the current air volume meets the standard. If not, the air supply volume of the air compressor is adjusted in time until it meets the standard.

[0013] The beneficial effect of the above-mentioned further improvement scheme is: the addition of an oxygen concentration sensor can more accurately monitor the oxygen concentration inside the fuel cell stack, rather than judging only by air flow. Because the fuel cell stack requires hydrogen and oxygen, monitoring the oxygen concentration is a more direct and accurate method, which can accurately control the load change process and is more conducive to ensuring the performance of the engine.

[0014] Furthermore, the air compression control device further comprises:

[0015] A data transceiver unit, used to receive the real-time gas flow rate and the real-time output current of the fuel cell, and transmit them to a control unit and a remote control device;

[0016] A control unit is used to determine whether a cross-operating condition load change occurs after starting according to a user's load change instruction; and, if it occurs, determine the target gas flow at multiple different times within a preset time period after the start time according to the load change target in the load change instruction, and control the air compressor to respond at an intake speed exceeding the corresponding target gas flow at each of the different times; if it does not occur, identify the difference between the real-time gas flow and the current operating condition target gas flow, and control the air compressor to respond accordingly according to the difference; and, in the above-mentioned response process, identify the initial time when the gas flow sensor measures each target gas flow, obtain the output current of the fuel cell corresponding to each initial time, determine whether the load change process is stable, and if it is not stable, control the air compressor to make a supplementary response at this time until it stabilizes and adjusts the current gas flow to the gas flow corresponding to the load change target;

[0017] The execution unit is used to increase or decrease the power supply current of the air compressor under the control of the control unit to change the intake speed.

[0018] The beneficial effects of the above further improvement scheme are: directly driving the change of the corresponding air volume through the response of the current, reducing the sensors required during the load change process, saving costs, and improving the stability of the control system.

[0019] Further, the execution unit includes a variable resistor or a reactor connected in series with the fuel cell air compressor.

[0020] The beneficial effect of the above further improvement scheme is that the power supply current of the air compressor can be adjusted by changing the variable resistance or reactance, which reduces the burden on the power supply system, reduces the control difficulty of the control system, and improves the control stability.

[0021] Further, the control unit executes the following procedure to determine whether cross-operating condition load change occurs:

[0022] Identifying a load change target contained in a load change instruction; the load change target is a current amplitude corresponding to a target power;

[0023] The actual output current amplitude of the fuel cell at the current moment is obtained and compared with the above-mentioned load change target. If the difference between the two is within the preset range, it is determined that no cross-operating condition load change occurs; otherwise, it is determined that a cross-operating condition load change occurs.

[0024] The beneficial effect of the above further improvement scheme is that it can be more effectively close to the actual application scenario and meet the power demand logic in actual vehicle operation.

[0025] Further, after determining that a load change occurs across operating conditions, the control unit executes the following procedure:

[0026] According to the load change target and load change time in the load change instruction, determine the time of data collection and the target gas flow rate at multiple different times within a preset period after the start time; the preset period is 1 / 6 to 1 / 2 of the load change time;

[0027] Determine a target air intake speed and a target power supply current of the air compressor corresponding to each of the above target gas flows;

[0028] Controlling the power supply current of the air compressor to exceed the corresponding target power supply current at the first moment within the preset time period, and operating in response to exceeding the target intake speed;

[0029] After the first moment and before the second moment, identify the initial moment when the gas flow sensor measures the corresponding target gas flow, obtain the output current of the fuel cell corresponding to the initial moment, and judge whether the load change process is stable. If the output current is equal to the current corresponding to the target gas flow, it is determined to be stable; otherwise, it is determined to be unstable, and control the air compressor to start adjusting the power supply current of the air compressor at the initial moment until it is stable, thereby completing the adjustment at the first moment;

[0030] Repeat the above control steps to complete the adjustment of the time after the first time in the preset time period;

[0031] After the adjustment is completed, the air compressor is controlled to adjust the current gas flow rate to the gas flow rate corresponding to the load change target before the load change time ends.

[0032] The beneficial effect of the above further improvement scheme is that it can be more effectively close to the actual application scenario and meet the power demand logic in actual vehicle operation.

[0033] Further, after determining that no cross-operating condition load change occurs, the control unit executes the following procedure:

[0034] Determine the target gas flow corresponding to the current working conditions;

[0035] Obtaining the difference between the real-time gas flow rate and the target gas flow rate, and controlling the air compressor to increase or decrease the power supply current to respond accordingly according to the difference;

[0036] Identify the initial moment when the gas flow sensor measures the target gas flow, obtain the output current of the fuel cell corresponding to the initial moment, and judge whether the load change process is stable. If the output current is equal to the current corresponding to the target gas flow, it is determined to be stable. Otherwise, it is determined to be unstable. Control the air compressor to adjust the power supply current of the air compressor at the initial moment to perform a supplementary response until it is stable, and execute the next step.

[0037] The air compressor is controlled to change the current gas flow to the gas flow corresponding to the load change target before the load change time ends.

[0038] The beneficial effect of the above further improvement scheme is: by adjusting and supplementing the air flow, it is ensured that the engine is not in a state of lack of air, thereby avoiding the reduction of engine performance.

[0039] Furthermore, it also includes a pressure sensor disposed on the inner wall of the output pipeline of the fuel cell air compressor;

[0040] The pressure sensor is used to collect the air pressure on the inner wall of the output pipeline and send it to the air compression control device;

[0041] The air compression control device is also used to compare the received air pressure on the inner wall of the output pipeline with a threshold value to determine whether the air pressure exceeds the standard at the current moment. Once it exceeds the standard, the air supply of the air compressor is reduced in time until it does not exceed the standard.

[0042] The beneficial effect of the above further improvement scheme is that after adding the pressure sensor, the load change process is made safer, the air pressure is prevented from exceeding the standard, and the service life of the fuel cell is greatly increased.

[0043] Furthermore, the air compression control device executes the following procedure to adjust the air supply volume of the air compressor:

[0044] Obtain the oxygen concentration of the air in the pipeline entering the stack at the current moment;

[0045] Compare the oxygen concentration with the threshold value to determine whether the current air volume meets the standard. If the two are equal, it is determined that the standard is met; otherwise, it is determined that the standard is not met and the next step is executed;

[0046] Determine whether the oxygen concentration is less than a threshold value. If so, increase the power supply current of the air compressor to increase the gas supply. Otherwise, reduce the power supply current of the air compressor to reduce the gas supply until the standard is met.

[0047] The beneficial effects of the above further improvement scheme are: accurate monitoring of the oxygen concentration entering the reactor, ensuring sufficient gas supply for the reaction, and more accurate and effective control.

[0048] On the other hand, an embodiment of the present invention provides a load changing method for a fuel cell engine, comprising the following steps:

[0049] Determine whether cross-operating condition load change occurs according to the user's load change instruction;

[0050] If a load change occurs across operating conditions, the real-time gas flow at the air inlet of the fuel cell engine is measured by a gas flow sensor, and the target gas flow at multiple different times after the start time is determined according to the load change target in the load change instruction, and the air compressor is controlled to respond at each of the different times with an intake speed exceeding the corresponding target gas flow; at the same time, the real-time output current of the fuel cell is measured by a current sensor, the initial time when the gas flow sensor measures each target gas flow, the output current of the fuel cell at the initial time is obtained, and it is judged whether the load change process is stable. If it is not stable, the air compressor is controlled to make a supplementary response at that time until the current gas flow is adjusted to the gas flow corresponding to the load change target after it becomes stable;

[0051] If no cross-operating load change occurs, the difference between the real-time gas flow and the target gas flow of the current operating condition is identified, and the air compressor is controlled to respond accordingly based on the difference. At the same time, the real-time output current of the fuel cell is measured by the current sensor, and the initial moment when the gas flow sensor measures each target gas flow is identified. The output current of the fuel cell at the initial moment is obtained to determine whether the load change process is stable. If it is not stable, the air compressor is controlled to make a supplementary response at that moment until the current gas flow is adjusted to the gas flow corresponding to the load change target after it becomes stable.

[0052] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the disclosure, nor is it intended to limit the scope of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The above and other objects, features and advantages of the present disclosure will become more apparent through a more detailed description of exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present disclosure.

[0054] Figure 1 A schematic diagram of the structure of a load changing device according to embodiment 1 of the present invention is shown;

[0055] Figure 2 A schematic diagram of the structure of a load changing device according to embodiment 2 of the present invention is shown;

[0056] Figure 3 A schematic diagram showing the principle of an air compression control device according to Embodiment 2 of the present invention is shown;

[0057] Figure 4 A schematic diagram showing the principle of load variation across working conditions according to Embodiment 2 of the present invention is shown. DETAILED DESCRIPTION

[0058] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present disclosure more thorough and complete, and to fully convey the scope of the present disclosure to those skilled in the art.

[0059] As used herein, the term "including" and its variations mean open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "based at least in part on". The terms "an example embodiment" and "an embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first", "second", etc. may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0060] Example 1

[0061] A specific embodiment of the present invention discloses a load changing device for a fuel cell engine, such as Figure 1 As shown, it includes a gas flow sensor, a current sensor, and an air compression control device. The output ends of the gas flow sensor and the current sensor are respectively connected to the input end of the air compression control device. The outlet end of the air compressor is connected to the inlet end of the fuel cell stack.

[0062] The gas flow sensor is installed at the air inlet of the fuel cell engine to measure the real-time gas flow at the installation location and send it to the air compression control device.

[0063] The current sensor is arranged at the output end of the fuel cell and is used to measure the real-time output current of the fuel cell and send it to the air compression control device.

[0064] An air compression control device is used to determine whether a cross-operating condition load change occurs after being started according to a user's load change instruction; and, if it occurs, determine the target gas flow rates at multiple different times after the start time according to the load change target in the load change instruction, and control the air compressor to respond at each of the different times with an intake speed exceeding the corresponding target gas flow rate; if it does not occur, identify the difference between the real-time gas flow rate and the current operating condition target gas flow rate, and control the air compressor to respond accordingly according to the difference; and, in the above-mentioned response process, identify the initial moment when the gas flow sensor measures each target gas flow rate, obtain the output current of the fuel cell at each initial moment, determine whether the load change process is stable, and if it is not stable, control the air compressor to make a supplementary response at that moment until it stabilizes and adjusts the current gas flow rate to the gas flow rate corresponding to the load change target.

[0065] Compared with the prior art, the existing variable load control methods are all strategies based on the metering ratio required by the stack, i.e., the target metering ratio of the variable load. They fail to fully consider the flow lag caused by the air diffusion effect and the response hysteresis of the air compressor, and there is a lack of flow, i.e., it causes partial gas shortage, which has a huge impact on the performance and life of the stack. The above-mentioned variable load device provided in this embodiment fully considers the diffusion effect of air and the response hysteresis of the air compressor, and sets the metering ratio (gas flow) during the variable load process to be higher than the target metering ratio (target gas flow) required by the stack. After the metering ratio is increased, the air flow rate is increased, which can effectively slow down the gas shortage caused by gas diffusion and air compressor response hysteresis, and ensure the performance and life of the fuel cell engine.

[0066] Example 2

[0067] Based on the optimization of embodiment 1, the load changing device further includes an oxygen concentration sensor disposed in the air inlet pipeline of the fuel cell. The output end of the oxygen concentration sensor is connected to the input end of the air compression control device.

[0068] The oxygen concentration sensor is used to detect the oxygen concentration in the air in the stack pipeline in real time and send it to the air compression control device.

[0069] The air compression control device is also used to compare the received oxygen concentration with a threshold value to determine whether the current air volume meets the standard. If not, the air supply volume of the air compressor is adjusted in time until it meets the standard.

[0070] Preferably, the load changing device further comprises a pressure sensor arranged on the inner wall of the output pipeline of the fuel cell air compressor, wherein the output end of the pressure sensor is connected to the input end of the air compression control device.

[0071] The pressure sensor is used to collect the air pressure on the inner wall of the output pipeline and send it to the air compression control device.

[0072] The air compression control device is also used to compare the received air pressure on the inner wall of the output pipeline with a threshold value to determine whether the air pressure exceeds the standard at the current moment. Once it exceeds the standard, the air supply of the air compressor is reduced in time until it does not exceed the standard.

[0073] Preferably, the air compression control device further comprises a data transceiver unit, a control unit and an execution unit which are connected in sequence.

[0074] The data transceiver unit is used to receive the real-time gas flow and the real-time output current of the fuel cell, and transmit them to the control unit and the remote control device.

[0075] A control unit is used to determine whether a cross-operating condition load change occurs after being started according to a user's load change instruction; and, if it occurs, determine the target gas flow at multiple different times within a preset time period after the start time according to the load change target in the load change instruction, and control the air compressor to respond with an intake speed exceeding the corresponding target gas flow at each of the different times; if it does not occur, identify the difference between the real-time gas flow and the current operating condition target gas flow, and control the air compressor to respond accordingly according to the difference; and, in the above-mentioned response process, identify the initial time when the gas flow sensor measures each target gas flow, obtain the output current of the fuel cell corresponding to each initial time, determine whether the load change process is stable, and if it is not stable, control the air compressor to make a supplementary response at this time until it stabilizes and adjusts the current gas flow to the gas flow corresponding to the load change target.

[0076] The execution unit is used to increase or decrease the power supply current of the air compressor under the control of the control unit to change the intake speed. The execution unit further includes a variable resistor or reactor connected in series with the fuel cell air compressor, or other devices capable of changing the current size.

[0077] Preferably, the control unit executes the following procedure to determine whether cross-operating condition load change occurs:

[0078] S21 identifies the variable load target contained in the variable load instruction; the variable load target is the current amplitude corresponding to the target power;

[0079] S22. Obtain the actual output current amplitude of the fuel cell at the current moment, and compare it with the above-mentioned load change target. If the difference between the two is within the preset range, it is determined that no cross-operating condition load change occurs. Otherwise, it is determined that a cross-operating condition load change occurs. The engine operating condition is fixed, for example, one operating condition can be 50A and another operating condition can be 100A. In simple terms, as long as the current difference between the two operating conditions before and after the load change is within the preset range, it can be determined as non-cross-operating condition. If the current difference is large, it is a cross-operating condition load change.

[0080] Preferably, after determining that a load change across operating conditions occurs, the control unit executes the following procedure:

[0081] S23. According to the load change target and load change time in the load change instruction, determine the time of data collection and the target gas flow rate at multiple different times within a preset period after the start time; the preset period is 1 / 6 to 1 / 2 of the load change time; specifically, the set target gas flow rate shall not exceed the safety range of the fuel cell stack, because too high gas flow rate will cause engine performance to decline, and the specific target gas flow rate range also varies from fuel cell stack to fuel cell stack;

[0082] S24. Determine the target air intake speed and target power supply current of the air compressor corresponding to each target gas flow rate; specifically, the target air intake speed and target power supply current can be calibrated by actual measurement;

[0083] S25. Controlling the power supply current of the air compressor to exceed the corresponding target power supply current at the first moment within the preset period, and operating in response to exceeding the target intake speed; the specific extent of the excess varies depending on the air compressor (also called air compressor, or air compression equipment);

[0084] S26. After the first moment and before the second moment, identify the initial moment when the gas flow sensor measures the target gas flow, obtain the output current of the fuel cell corresponding to the initial moment, and judge whether the load change process is stable. If the output current is equal to the current corresponding to the target gas flow, it is determined to be stable; otherwise, it is determined to be unstable, and control the air compressor to adjust the power supply current of the air compressor from the initial moment until it is stable, thereby completing the adjustment at the first moment;

[0085] S27 repeats the above control steps to complete the adjustment of the first moment after the preset period;

[0086] S28. After the adjustment is completed, the air compressor is controlled to adjust the current gas flow rate to the gas flow rate corresponding to the load change target before the load change time ends. For example, Figure 3 shown.

[0087] Preferably, after determining that no cross-operating condition load change occurs, the control unit executes the following procedure:

[0088] S29. Determine the target gas flow rate corresponding to the current operating condition;

[0089] S210 obtains the difference between the real-time gas flow rate and the target gas flow rate, and controls the air compressor to increase or decrease the power supply current in response to the difference;

[0090] S211. Identify the initial moment when the gas flow sensor measures the target gas flow, obtain the output current of the fuel cell corresponding to the initial moment, and determine whether the load change process is stable. If the output current is equal to the current corresponding to the target gas flow, it is determined to be stable. Otherwise, it is determined to be unstable, and the air compressor is controlled to adjust the power supply current of the air compressor at the initial moment to perform a supplementary response until it is stable, and then execute the next step;

[0091] S212. Control the air compressor to change the current gas flow rate to the gas flow rate corresponding to the load change target before the load change time ends. For example, Figure 3 Preferably, the air compression control device executes the following procedure to adjust the air supply volume of the air compressor:

[0092] S213. Obtaining the oxygen concentration of the air in the stack pipeline at the current moment;

[0093] S214. The oxygen concentration is compared with the threshold value to determine whether the current air volume meets the standard. If the two are equal, it is determined that the standard is met. Otherwise, it is determined that the standard is not met and the next step is executed;

[0094] S215. Determine whether the oxygen concentration is less than a threshold value. If so, increase the power supply current of the air compressor to increase the gas supply. Otherwise, reduce the power supply current of the air compressor to reduce the gas supply until the oxygen concentration reaches the standard.

[0095] During implementation, the process from the operating point (which can be understood as the output current) from A to B, that is, from the current A to the current B, due to the performance and life requirements of the fuel cell stack, the air stoichiometric ratio (the ratio of the gas actually supplied to the fuel cell engine reaction and the gas theoretically required) is required. The target gas flow rates corresponding to the operating points A and B are a and b, respectively. In the prior art, due to the air diffusion effect and the response hysteresis of the air compressor during the load change process, the air needs to go through a certain period of time to reach the reaction zone, which will cause local gas shortage and affect the performance and life of the fuel cell stack. The actual gas flow rates of the load change process of this embodiment are a and b', respectively, where b'>b. During the load change process, the required stoichiometric ratio of the air increases, and the corresponding air flow increases. The air compressor needs to respond faster to reach the gas flow b'. At this time, due to the increase in air flow, the air diffuses faster, which effectively slows down the hysteresis effect of the air supply and ensures the performance and life of the fuel cell stack. The flow rate is monitored by a flow sensor at the air inlet of the fuel cell engine (or the air compressor inlet). When the flow value reaches the flow corresponding to the gas flow b', the delay time t minutes, and then gradually reduce to gas flow rate b.

[0096] For complex load changes, current points C and D are involved in the process, and the target gas flow rates required by the corresponding fuel cells are a, b, c, and d, respectively. In the process of load changes, the actual gas flow rates of operating points A and B are a and b', and the actual gas flow rates of C and D are c' and d', respectively. Among them, b'>b, c'>c, d'>d, and the air compressor responds to the air volume according to b', c', and d'. In the corresponding process, the air flow rate is monitored by the flow sensor at the front end of the air compressor. When the flow value reaches the volume corresponding to d', the delay time t minutes. Then gradually reduce the metering ratio to gas flow rate b, such as Figure 4 shown.

[0097] Compared with Example 1, the device provided in this embodiment further reduces local gas shortage caused by insufficient gas supply by oversupplying air during the load change process, weakens the insufficient gas supply caused by gas diffusion and air compressor hysteresis, and after the load change is completed, the original metering ratio (gas flow rate) is gradually restored after the performance of the single chip is stabilized.

[0098] Example 3

[0099] The present invention also discloses a load changing method using the device of embodiment 1 or embodiment 2, comprising the following steps:

[0100] S1. Determine whether cross-operating condition load change occurs according to the user's load change instruction;

[0101] S2. If a load change occurs across operating conditions, the real-time gas flow at the air inlet of the fuel cell engine is measured by a gas flow sensor, and the target gas flow at multiple different times after the start time is determined according to the load change target in the load change instruction, and the air compressor is controlled to respond at each of the different times with an intake speed exceeding the corresponding target gas flow; at the same time, the real-time output current of the fuel cell is measured by a current sensor, the initial time when the gas flow sensor measures each target gas flow, the output current of the fuel cell at the initial time is obtained, and it is judged whether the load change process is stable. If it is not stable, the air compressor is controlled to make a supplementary response at this time until the current gas flow is adjusted to the gas flow corresponding to the load change target after it becomes stable;

[0102] S3. If no cross-operating condition load change occurs, the difference between the real-time gas flow and the target gas flow of the current operating condition is identified, and the air compressor is controlled to respond accordingly based on the difference; at the same time, the real-time output current of the fuel cell is measured by the current sensor, the initial moment when the gas flow sensor measures each target gas flow, the output current of the fuel cell at the initial moment is obtained, and it is determined whether the load change process is stable. If it is not stable, the air compressor is controlled to make a supplementary response at that moment until it becomes stable and the current gas flow is adjusted to the gas flow corresponding to the load change target.

[0103] The embodiments of the present disclosure have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terms used herein are selected to best explain the principles of the embodiments, practical applications, or improvements over the prior art, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A load changing device for a fuel cell engine, characterized in that: include: A gas flow sensor is arranged at the air inlet of the fuel cell engine to measure the real-time gas flow at the arranged location and send it to the air compression control device; A current sensor is provided at the output end of the fuel cell and is used to measure the real-time output current of the fuel cell and send it to the air compression control device; Air compression control equipment, used to determine whether cross-operating load change occurs after starting according to the user's load change instruction; And, if it occurs, the target gas flow rates at multiple different times after the start time are determined according to the load change target in the load change instruction, and the air compressor is controlled to respond with an intake speed exceeding the corresponding target gas flow rate at each of the different times; if it does not occur, the difference between the real-time gas flow rate and the current operating target gas flow rate is identified, and the air compressor is controlled to respond accordingly according to the difference; and, in the above-mentioned response process, the initial moment when the gas flow sensor measures each target gas flow rate is identified, the output current of the fuel cell at each initial moment is obtained, and it is judged whether the load change process is stable; if it is not stable, the air compressor is controlled to make a supplementary response at that moment until the current gas flow rate is adjusted to the gas flow rate corresponding to the load change target after it becomes stable.

2. The load variable device for a fuel cell engine according to claim 1, characterized in that: It also includes an oxygen concentration sensor disposed in an air inlet pipeline of the fuel cell; The oxygen concentration sensor is used to detect the oxygen concentration in the air in the stack pipeline in real time and send it to the air compression control device; The air compression control device is also used to compare the received oxygen concentration with a threshold value to determine whether the current air volume meets the standard. If not, the air supply volume of the air compressor is adjusted in time until it meets the standard.

3. The load variable device for a fuel cell engine according to claim 1 or 2, characterized in that: The air compression control device further comprises: A data transceiver unit, used to receive the real-time gas flow rate and the real-time output current of the fuel cell, and transmit them to a control unit and a remote control device; A control unit is used to determine whether a cross-operating condition load change occurs after being started according to a user's load change instruction; and, if it occurs, determining the target gas flow rates at multiple different times within a preset period after the start time according to the load change target in the load change instruction, and controlling the air compressor to respond at each of the different times with an intake speed exceeding the corresponding target gas flow rate; and, if it does not occur, identifying the difference between the real-time gas flow rate and the target gas flow rate of the current working condition, and controlling the air compressor to respond accordingly according to the difference; and, in the above-mentioned response process, identifying the initial time when the gas flow sensor measures each target gas flow rate, obtaining the output current of the fuel cell corresponding to each initial time, judging whether the load change process is stable, and if it is not stable, controlling the air compressor to make a supplementary response at that time, and adjusting the current gas flow rate to the gas flow rate corresponding to the load change target after stabilization; The execution unit is used to increase or decrease the power supply current of the air compressor under the control of the control unit to change the intake speed.

4. The load variable device for a fuel cell engine according to claim 3, characterized in that: The execution unit includes a variable resistor or a reactor connected in series with the fuel cell air compressor.

5. The load variable device for a fuel cell engine according to claim 4, characterized in that: The control unit executes the following procedure to determine whether a load change across operating conditions occurs: Identifying a load change target contained in a load change instruction; the load change target is a current amplitude corresponding to a target power; The actual output current amplitude of the fuel cell at the current moment is obtained and compared with the above-mentioned load change target. If the difference between the two is within the preset range, it is determined that no cross-operating condition load change occurs; otherwise, it is determined that a cross-operating condition load change occurs.

6. The load variable device for a fuel cell engine according to claim 4 or 5, characterized in that: After determining that a load change occurs across operating conditions, the control unit executes the following procedures: Determine the time of data collection and the target gas flow rate at multiple different times within a preset period after the start time according to the load change target and load change time in the load change instruction; The preset time period is 1 / 6 to 1 / 2 of the load change time; Determine a target air intake speed and a target power supply current of the air compressor corresponding to each of the above target gas flows; Controlling the power supply current of the air compressor to exceed the corresponding target power supply current at the first moment within the preset time period, and operating in response to exceeding the target intake speed; After the first moment and before the second moment, identify the initial moment when the gas flow sensor measures the corresponding target gas flow, obtain the output current of the fuel cell corresponding to the initial moment, and judge whether the load change process is stable. If the output current is equal to the current corresponding to the target gas flow, it is determined to be stable; otherwise, it is determined to be unstable, and control the air compressor to start adjusting the power supply current of the air compressor at the initial moment until it is stable, thereby completing the adjustment at the first moment; Repeat the above control steps to complete the adjustment of the time after the first time in the preset time period; After the adjustment is completed, the air compressor is controlled to adjust the current gas flow rate to the gas flow rate corresponding to the load change target before the load change time ends.

7. The load variable device for a fuel cell engine according to claim 6, characterized in that: After determining that no cross-operating condition load change occurs, the control unit executes the following procedure: Determine the target gas flow corresponding to the current working conditions; Obtaining the difference between the real-time gas flow rate and the target gas flow rate, and controlling the air compressor to increase or decrease the power supply current to respond accordingly according to the difference; Identify the initial moment when the gas flow sensor measures the target gas flow, obtain the output current of the fuel cell corresponding to the initial moment, and judge whether the load change process is stable. If the output current is equal to the current corresponding to the target gas flow, it is determined to be stable. Otherwise, it is determined to be unstable. Control the air compressor to adjust the power supply current of the air compressor at the initial moment to perform a supplementary response until it is stable, and execute the next step. The air compressor is controlled to change the current gas flow to the gas flow corresponding to the load change target before the load change time ends.

8. The load variable device for a fuel cell engine according to any one of claims 1-2, 4-5, and 7, characterized in that: Also included is a pressure sensor disposed on the inner wall of the fuel cell air compressor output pipeline; The pressure sensor is used to collect the air pressure on the inner wall of the output pipeline and send it to the air compression control device; The air compression control device is also used to compare the received air pressure on the inner wall of the output pipeline with a threshold value to determine whether the air pressure exceeds the standard at the current moment. Once it exceeds the standard, the air supply of the air compressor is reduced in time until it does not exceed the standard.

9. The load variable device for a fuel cell engine according to claim 2, characterized in that: The air compression control device performs the following procedure to adjust the air supply volume of the air compressor: Obtain the oxygen concentration of the air in the pipeline entering the stack at the current moment; Compare the oxygen concentration with the threshold value to determine whether the current air volume meets the standard. If the two are equal, it is determined that the standard is met; otherwise, it is determined that the standard is not met and the next step is executed; Determine whether the oxygen concentration is less than a threshold value. If so, increase the power supply current of the air compressor to increase the gas supply. Otherwise, reduce the power supply current of the air compressor to reduce the gas supply until the standard is met.

10. A load changing method for a fuel cell engine, characterized in that: The steps include: Determine whether cross-operating condition load change occurs according to the user's load change instruction; If a load change occurs across operating conditions, the real-time gas flow at the air inlet of the fuel cell engine is measured by a gas flow sensor, and the target gas flow at multiple different times after the start time is determined according to the load change target in the load change instruction, and the air compressor is controlled to respond at each of the different times with an intake speed exceeding the corresponding target gas flow; at the same time, the real-time output current of the fuel cell is measured by a current sensor, the initial time when the gas flow sensor measures each target gas flow, the output current of the fuel cell at the initial time is obtained, and it is judged whether the load change process is stable. If it is not stable, the air compressor is controlled to make a supplementary response at that time until the current gas flow is adjusted to the gas flow corresponding to the load change target after it becomes stable; If no cross-operating load change occurs, the difference between the real-time gas flow and the target gas flow of the current operating condition is identified, and the air compressor is controlled to respond accordingly based on the difference. At the same time, the real-time output current of the fuel cell is measured by the current sensor, and the initial moment when the gas flow sensor measures each target gas flow is identified. The output current of the fuel cell at the initial moment is obtained to determine whether the load change process is stable. If it is not stable, the air compressor is controlled to make a supplementary response at that moment until the current gas flow is adjusted to the gas flow corresponding to the load change target after it becomes stable.

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