Fuel cell voltage control method and system under power grid disturbance

Abstract

The invention provides a fuel cell voltage control method and system under power grid disturbance, and belongs to the technical field of fuel cell voltage control. Whether power grid disturbance under low-voltage ride-through exists or not is judged according to the power grid operation state detected by the power grid disturbance detection assembly, when disturbance exists, a differential tracker is adopted to track and filter the voltage in the current state, and uncertain factors of a fuel cell are observed based on a disturbance observer; and then, inputting results obtained by the differential tracker and the disturbance observer into a nonlinear error feedback compensator to generate a reaction gas compensation amount, and adjusting a reaction gas excess coefficient and a reaction gas circulation rate, so that the voltage is recovered to be stable, and voltage control is realized. According to the method, the voltage of the fuel cell can be quickly and effectively controlled under the power grid disturbance of low-voltage ride-through, so that the service life of the fuel cell is prolonged, and the working environment of the fuel cell is continuously kept stable.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel cell voltage control, and particularly relates to a fuel cell voltage control method and system under grid disturbances. Background Art

[0002] The statements in this part only provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] As an efficient and environmentally friendly energy conversion device, fuel cells are gradually becoming an important development direction in the energy field. Its basic principle is to directly convert the chemical energy in the fuel into electrical energy, with almost no harmful emissions generated during the process, so it is regarded as a key part of future energy technology. Currently, fuel cells (such as proton exchange membrane fuel cells PEMFC) are most widely used in the transportation field, especially in the automotive industry, and fuel cell vehicles (FCEV) have also received extensive attention for their zero emissions and high energy conversion efficiency. In addition, fuel cells also play an important role in high-reliability power supply scenarios such as data centers, hospitals, and communication base stations.

[0004] However, although fuel cell technology has many advantages, when connected to the grid, fuel cells will inevitably experience grid disturbance phenomena under low voltage ride-through, and fuel cells cannot be used normally during this phenomenon. For this reason, technicians in related fields have adopted many control methods to improve fuel cells, but these control methods still have some technical problems, such as:

[0005] (1) When low voltage ride-through occurs, existing fuel cell control methods mostly choose to be powered by additional backup components (such as uninterruptible power supplies), but this requires adding other power supply components on the basis of existing fuel cells. That is to say, relying solely on a single fuel cell cannot effectively control the voltage value and maintain its internal stability, and it is difficult to independently cope with grid disturbances under low voltage ride-through; moreover, this will undoubtedly increase the construction cost.

[0006] (2) In the prior art, there are also methods to increase the voltage of the fuel cell directly or directly increase the amount of reaction gas to increase the voltage value of the fuel cell. However, the increased voltage value and the amount of reaction gas are determined based on experience, which is likely to cause instability inside the battery, abnormal temperature, etc. Therefore, the voltage is not easily controlled within the optimal range, which will also seriously affect the life of the fuel cell. Summary of the Invention

[0007] To overcome the deficiencies of the above-mentioned existing technologies, the present invention provides a fuel cell voltage control method and system under grid disturbances, which can accurately and effectively control the voltage of the fuel cell under grid disturbances with low voltage ride-through, thereby extending the service life of the fuel cell and maintaining the working environment of the fuel cell to remain stable continuously.

[0008] To achieve the above object, one or more embodiments of the present invention provide the following technical solutions:

[0009] The first aspect of the present invention provides a fuel cell voltage control method under grid disturbances.

[0010] A fuel cell voltage control method under grid disturbances includes:

[0011] Based on a grid disturbance detection component, the operating state of the grid is detected in real time, and it is judged whether there is a grid disturbance under low voltage ride-through according to the operating state of the grid;

[0012] When there is a grid disturbance, a differential tracker is used to track and filter the voltage in the current state, and an uncertainty factor of the fuel cell is observed based on a disturbance observer; subsequently, the results obtained by the differential tracker and the disturbance observer are simultaneously input into a non-linear error feedback compensator to determine the reaction gas compensation amount for inputting into the fuel cell;

[0013] According to the obtained reaction gas compensation amount, the reaction gas excess coefficient and the reaction gas circulation rate are adjusted to make the voltage recover to stability, thereby realizing the voltage control of the fuel cell.

[0014] Further, judging whether there is a grid disturbance under low voltage ride-through according to the operating state of the grid includes: when the phase voltage between any two of the three-phase power of the grid is lower than a preset first phase voltage threshold, it is considered that there is a grid disturbance under low voltage ride-through.

[0015] Further, the differential tracker is expressed as:

[0016]

[0017] u r (t + 1) and u r (t) respectively represent the pre-tracked voltages of the differential tracker at time t + 1 and time t, and respectively represent the derivatives of the pre-tracked voltages u r (t + 1) and u r (t), T d represents the sampling period, and fhan(t) represents the fastest comprehensive function.

[0018] Further, the uncertainty factors of the fuel cell are observed based on a disturbance observer, where the uncertainty factors include load current disturbance, ambient temperature disturbance, and reaction gas flow rate change in the fuel cell.

[0019] Further, based on a built-in nonlinear feedback function, the nonlinear error feedback compensator generates a reaction gas compensation amount for input to the fuel cell based on proportional-derivative control parameters.

[0020] Further, the reaction gas excess coefficient and the reaction gas recycle ratio are adjusted according to the obtained reaction gas compensation amount. Specifically, the obtained reaction gas compensation amount and the reaction gas amount actually introduced into the fuel cell in the previous state are used as the total reaction gas input amount and input into the fuel cell together; by increasing the reaction gas input amount, the reaction gas excess coefficient and the reaction gas recycle ratio are increased, thereby increasing the voltage.

[0021] The second aspect of the present invention provides a fuel cell voltage control system under grid disturbance.

[0022] A fuel cell voltage control system under grid disturbance includes: a fuel cell stack, a grid disturbance detection component, a first control component, and a second control component; wherein, the first control component consists of a differential tracker, a disturbance observer, and a nonlinear error feedback compensator;

[0023] The grid disturbance detection component is configured to: detect the grid operation state in real time and determine whether there is a grid disturbance under low voltage ride-through according to the grid operation state;

[0024] The first control component is configured to: when there is a grid disturbance, use the differential tracker to track and filter the voltage in the current state, and observe the uncertainty factors of the fuel cell based on the disturbance observer; subsequently, input the results obtained by the differential tracker and the disturbance observer into the nonlinear error feedback compensator at the same time to determine the reaction gas compensation amount for input to the fuel cell;

[0025] The second control component is configured to: adjust the reaction gas excess coefficient and the reaction gas recycle ratio according to the obtained reaction gas compensation amount to make the voltage recover to stability, thereby realizing the voltage control of the fuel cell.

[0026] Further, the second control component includes an air compressor and a recycle pump; wherein, the air compressor is used to adjust the reaction gas excess coefficient by adjusting the reaction gas input amount, and the recycle pump is used to adjust the reaction gas recycle ratio.

[0027] Further, the first port of the air compressor and the second port of the circulation pump are respectively connected to the cathode inlet and the cathode outlet of the fuel cell stack. At the same time, the second port of the air compressor is connected to the first port of the circulation pump; the third port of the air compressor and the third port of the circulation pump are both connected to the second control component, and the other end interface of the second control component is connected to the grid disturbance detection component, and the other end of the grid disturbance detection component is connected to the power grid.

[0028] Further, the grid disturbance detection component includes a first acquisition device, a second acquisition device, and a third acquisition device, which are used to directly obtain the voltage signal of the connected power grid to facilitate real-time detection of the power grid operation state.

[0029] The above one or more technical solutions have the following beneficial effects:

[0030] (1) When there is a power grid disturbance under low voltage ride-through, the present invention first uses a differential tracker to track and filter the voltage, and observes the uncertain factors of the fuel cell based on a disturbance observer; subsequently, the results obtained by the differential tracker and the disturbance observer are simultaneously input into a non-linear error feedback compensator to determine the compensation amount of the reaction gas input to the fuel cell. By increasing the compensation amount of the reaction gas, the voltage is indirectly increased. The entire process can quickly stabilize the internal voltage without any external standby components to replace the fuel cell for power supply, and moreover, the construction cost can be reduced.

[0031] (2) Through the mutual cooperation among the differential tracker, the disturbance observer, and the non-linear error feedback compensator, the present invention can accurately determine the compensation amount of the reaction gas that needs to be increased. Compared with the prior art, this adjustment method can keep the internal operating environment and temperature of the fuel cell normal. Therefore, based on the voltage control method provided by the present invention, the voltage can be better controlled within the optimal range, and thus, under the power grid disturbance of low voltage ride-through, the voltage of the fuel cell can be accurately and effectively controlled, thereby extending the service life of the fuel cell and maintaining the working environment of the fuel cell continuously stable.

[0032] The advantages of the additional aspects of the present invention will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present invention. Description of the Drawings

[0033] The specification drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0034] Figure 1 It is a flowchart of a fuel cell voltage control method under a power grid disturbance in the first embodiment of the present invention.

[0035] Figure 2 This is a schematic diagram of the structural composition of a fuel cell voltage control system under grid disturbances in the second embodiment of the present invention. Detailed implementation manners

[0036] It should be noted that the following detailed descriptions are all exemplary and are intended to provide further explanations of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0037] It should be noted that the terms used herein are only for describing specific implementation manners and are not intended to limit the exemplary embodiments according to the present invention.

[0038] Without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0039] Embodiment 1

[0040] This embodiment discloses a fuel cell voltage control method under grid disturbances.

[0041] As Figure 1 shown, a fuel cell voltage control method under grid disturbances includes:

[0042] Step S1: Based on the grid disturbance detection component, the grid operation state is detected in real time, and it is judged whether there is a grid disturbance under low voltage ride-through according to the grid operation state;

[0043] Step S2: When there is a grid disturbance, a differential tracker is used to track and filter the voltage in the current state, and the uncertainty factors of the fuel cell are observed based on a disturbance observer; subsequently, the results obtained by the differential tracker and the disturbance observer are simultaneously input into a non-linear error feedback compensator to determine the reaction gas compensation amount for inputting into the fuel cell;

[0044] Step S3: According to the obtained reaction gas compensation amount, the reaction gas excess coefficient and the reaction gas circulation rate are adjusted to make the voltage return to stability, thereby realizing the voltage control of the fuel cell.

[0045] Based on the above process, the present invention can accurately and effectively control the voltage of the fuel cell under grid disturbances with low voltage ride-through, thereby prolonging the service life of the fuel cell and maintaining the working environment of the fuel cell continuously stable. For the convenience of understanding the technical solution of the present invention, the following further explains and illustrates the specific implementation steps in the technical solution of the present invention.

[0046] Step S1: Based on the grid disturbance detection component, the grid operation state is detected in real time, and it is judged whether there is a grid disturbance under low voltage ride-through according to the grid operation state.

[0047] Step S1-1: Based on the power grid disturbance detection component, the operating state of the power grid is detected in real time

[0048] The power grid disturbance detection component includes a first acquisition device, a second acquisition device, and a third acquisition device. The three acquisition devices are used to directly obtain the voltage signals of the connected power grid to facilitate the real-time detection of the operating state of the power grid. Among them, the first acquisition device, the second acquisition device, and the third acquisition device respectively collect the three-phase voltages of the power grid by directly connecting to the power grid.

[0049] Among them, the first acquisition device, the second acquisition device, and the third acquisition device are all high-precision voltage sensors. In this embodiment, the first acquisition device is connected to the A phase of the power grid, and the voltage of the A phase is measured through the high-precision voltage sensor; the second acquisition device is connected to the B phase of the power grid, and the voltage of the B phase is also measured through the high-precision voltage sensor; the third acquisition device is connected to the C phase of the power grid to measure the voltage of the C phase. Before the first acquisition device, the second acquisition device, and the third acquisition device are officially used, parameter configuration needs to be carried out respectively, including setting the sampling frequency, calibrating the voltage sensor, etc. The parameter configuration can be carried out through the physical buttons, touch screen interface or remote communication interface on the acquisition device.

[0050] Step S1-2: Determine whether there is a power grid disturbance under low voltage ride-through according to the operating state of the power grid

[0051] The power grid disturbance detection component further includes a judgment device. The judgment device can specifically be a small PLC programmable logic controller, and is connected to the acquisition device through a communication interface, and is used to receive the voltage data collected by the first acquisition device, the second acquisition device, and the third acquisition device and judge the operating state of the power grid. It should be noted that the judgment device can also be replaced by other devices according to needs, as long as it can perform ratio judgment based on the collected voltage.

[0052] Preset a first inter-phase voltage threshold and a second inter-phase voltage threshold, where the first inter-phase voltage threshold is less than the second inter-phase voltage threshold. Use a judgment device to compare the three-phase voltage values of the received power grid with the first inter-phase voltage threshold and the second inter-phase voltage threshold. When the inter-phase voltage between any two of the three-phase voltages of the received power grid is less than the set first inter-phase voltage threshold, it is considered that the voltage of the power grid has dropped too much, that is, low voltage ride-through occurs; at this time, the judgment device will send a voltage control start signal to remind the first control component to start voltage control. When the inter-phase voltage between any two of the three-phase voltages of the received power grid is greater than the set second inter-phase voltage threshold, it indicates that the voltage has been regulated to the normal range through the voltage control method of the present invention. At this time, the judgment device will send a voltage control end signal to remind the first control component to stop voltage control. Further, in the actual implementation process, the code '0' can be used as the voltage control start signal, and the code '1' can be used as the voltage control end signal.

[0053] Step S2: When there is a power grid disturbance, use a differential tracker to track and filter the voltage in the current state, and observe the uncertain factors of the fuel cell based on a disturbance observer; then, input the results obtained by the differential tracker and the disturbance observer into a non-linear error feedback compensator at the same time to determine the reaction gas compensation amount for inputting into the fuel cell. In this embodiment, the selected reaction gas is hydrogen, of course, this is not the only choice, and the specific reaction gas can be selected according to the actual situation.

[0054] When the first control component receives the voltage control start signal, it starts to execute voltage control. Specifically: The first control component determines the reaction gas compensation amount for inputting into the fuel cell by tracking the voltage state of the fuel cell, and provides preparation for subsequent voltage control by increasing an appropriate amount of reaction gas. Among them, the first control component includes a differential tracker, a disturbance observer, and a non-linear error feedback compensator. The determination of the reaction gas compensation amount based on the first control component can be achieved through the following steps.

[0055] Step S2-1: When there is a power grid disturbance, use a differential tracker to track and filter the voltage in the current state.

[0056] The main function of the differential tracker is to quickly and smoothly lock the control signal of the pre-tracked voltage and calculate its differential signal; at the same time, filter the locked pre-tracked voltage control signal to reduce noise interference. Specifically, the differential tracker is expressed as:

[0057]

[0058] u r (t + 1) and u r(t) represents the pre-tracking voltages of the differential tracker at time t + 1 and time t, and represent the derivatives of the pre-tracking voltages u r (t + 1) and u r (t) respectively, T d represents the sampling period, and fhan(t) represents the fastest synthesis function.

[0059] As the fastest synthesis function, fhan(t) is mathematically expressed as:

[0060]

[0061] where, v s represents the speed factor for adjusting the tracking speed, d represents the length of the linear interval, h represents the sampling step, c represents the number of segments of the linear segment, c0 represents the control coefficient of the linear segment, d0 represents the total number of steps under the total linear interval length, and u0 represents the actual output voltage of the fuel cell.

[0062] Step S2-2: Observe the uncertainty factors of the fuel cell based on the disturbance observer.

[0063] After tracking and filtering the voltage in the current state, observe the uncertainty factors of the fuel cell based on the disturbance observer. Among them, the uncertainty factors include load current disturbance, environmental temperature disturbance, and reaction gas flow change in the fuel cell. These uncertainty factors are taken together as the total disturbance factor for real-time estimation. Specifically, the main algorithm of the disturbance observer can be expressed as:

[0064]

[0065] where, e represents the tracking error, g1(t), g2(t), and g3(t) represent the estimated values of the load current disturbance, environmental temperature disturbance, and reaction gas flow at time t respectively, g1(t + 1), g2(t + 1), and g3(t + 1) represent the estimated values of the load current disturbance, environmental temperature disturbance, and reaction gas flow at time t + 1 respectively; β1 represents the proportional coefficient, β2 represents the differential coefficient, β3 represents the gain coefficient; nfal() represents the non-linear function, δ represents the length of the linear interval, b0 represents the estimated value of the input gain b, y(t) represents the control quantity at time t, y0(t) represents the expected control quantity at time t, and c1 and c2 represent the control coefficients of the non-linear segment.

[0066] Furthermore, when the estimated value of the reaction gas flow is small enough different from the total disturbance error, the designed transfer function can be changed to the following formula, that is:

[0067]

[0068] Among them, represents the transfer function value, G represents the total disturbance error, g3 represents the estimated value of the reaction gas flow rate, and y0 represents the reaction gas compensation amount input to the fuel cell. On this basis, it is only necessary to use the nonlinear error feedback compensator to perform the feedback of the reaction gas compensation amount.

[0069] Step S2-3: Input the results obtained by the differential tracker and the disturbance observer into the nonlinear error feedback compensator simultaneously to determine the reaction gas compensation amount input to the fuel cell.

[0070] Based on the internal nonlinear feedback function, the nonlinear error feedback compensator generates the reaction gas compensation amount input to the fuel cell based on the proportional-derivative control parameters. Specifically, the nonlinear function nfal(.) can be expressed as:

[0071]

[0072] Among them, c f represents the nonlinear segment control coefficient, and δ represents the linear interval length. Further, the feedback control algorithm based on the proportional-derivative control parameters is expressed as:

[0073] y0 = β1*nfal(e1, c1, δ) + β2*nfal(e2, c2, δ);

[0074] Among them, y0 represents the reaction gas compensation amount input to the fuel cell, and e1 and e2 respectively represent the tracking errors of the load current disturbance and the ambient temperature disturbance.

[0075] Step S3: Adjust the reaction gas excess coefficient and the reaction gas recycle ratio according to the obtained reaction gas compensation amount to make the voltage stable, and then realize the voltage control of the fuel cell.

[0076] Adjust the reaction gas excess coefficient and the reaction gas recycle ratio according to the obtained reaction gas compensation amount. Specifically, take the obtained reaction gas compensation amount and the actual reaction gas amount input to the fuel cell in the previous state as the total reaction gas input amount, and input them into the fuel cell together; increase the reaction gas input amount to increase the reaction gas excess coefficient and the reaction gas recycle ratio, and then increase the voltage. Among them, the reaction gas excess coefficient represents the ratio of the reaction gas amount entering the fuel cell through the cathode inlet of the fuel cell to the reaction gas amount actually participating in the reaction, and the reaction gas amount represents the reaction gas amount entering the fuel cell through the cathode inlet of the fuel cell; the reaction gas recycle ratio represents the ratio of the reaction gas discharged from the cathode outlet of the fuel cell and re-entering the fuel cell through the cathode inlet again, relative to the percentage of the total reaction gas amount flowing into the fuel cell.

[0077] When low-voltage ride-through occurs, the first control component generates the required reaction gas compensation amount. At this time, the second control component starts to increase the input amount of the reaction gas according to the required reaction gas compensation amount. Specifically, the second control component includes an air compressor and a circulation pump. The air compressor can use the obtained reaction gas compensation amount and the amount of the reaction gas actually introduced into the fuel cell in the previous state as the total reaction gas input amount, and input them into the fuel cell together. Thus, the gas excess coefficient can be increased. As the gas excess coefficient increases, the working voltage of the stack in the fuel cell will rise. At the same time, according to the increased gas excess coefficient, the gas recirculation rate is reduced so that the reaction gas throughput of the stack in the fuel cell is controlled within a reasonable range.

[0078] Further, adjusting the gas recirculation rate according to the gas excess coefficient can be achieved through the following formula, that is:

[0079]

[0080] Q represents the recirculation rate of the reaction gas, A represents the initial value of the reaction gas recirculation rate, and B represents the gas excess coefficient.

[0081] Thus, when low-voltage ride-through occurs, the present invention can control the working voltage of the fuel cell within the normal range. When the low-voltage ride-through ends, the voltage control can be terminated. Therefore, the present invention can accurately and effectively control the voltage of the fuel cell under the power grid disturbance of low-voltage ride-through, thereby extending the service life of the fuel cell and maintaining the working environment of the fuel cell to remain stable continuously.

[0082] Embodiment 2

[0083] This embodiment discloses a fuel cell voltage control system under power grid disturbance.

[0084] As Figure 2 shown, a fuel cell voltage control system under power grid disturbance includes: a stack, a power grid disturbance detection component, a first control component, and a second control component; wherein, the first control component is composed of a differential tracker, a disturbance observer, and a non-linear error feedback compensator;

[0085] The power grid disturbance detection component is configured to: detect the operation state of the power grid in real time, and judge whether there is a power grid disturbance under low-voltage ride-through according to the operation state of the power grid;

[0086] The first control component is configured to: when there is a power grid disturbance, use a differential tracker to track and filter the voltage in the current state, and observe the uncertain factors of the fuel cell based on a disturbance observer; subsequently, input the results obtained by the differential tracker and the disturbance observer into a non-linear error feedback compensator simultaneously to determine the compensation amount of the reaction gas for input into the fuel cell.

[0087] The second control component is configured to: adjust the reaction gas excess coefficient and the reaction gas recycle ratio according to the obtained reaction gas compensation amount, so as to restore the voltage to stability, and further realize the voltage control of the fuel cell.

[0088] Furthermore, the second control component includes an air compressor and a recycle pump; wherein, the air compressor is used to adjust the reaction gas excess coefficient by adjusting the reaction gas input amount, and the recycle pump is used to adjust the reaction gas recycle ratio.

[0089] Furthermore, the first port of the air compressor and the second port of the recycle pump are respectively connected to the cathode inlet and the cathode outlet of the stack. At the same time, the second port of the air compressor and the first port of the recycle pump are connected; the third port of the air compressor and the third port of the recycle pump are both connected to the second control component, the other end interface of the second control component is connected to a power grid disturbance detection component, and the other end of the power grid disturbance detection component is connected to the power grid.

[0090] Furthermore, the power grid disturbance detection component includes a first acquisition device, a second acquisition device and a third acquisition device, which are used to directly obtain the voltage signal of the connected power grid, so as to detect the operation state of the power grid in real time.

[0091] Each step involved in the device of the above Embodiment 2 corresponds to that of Method Embodiment 1, and the specific implementation manner can refer to the relevant description part of Embodiment 1.

[0092] Those skilled in the art should understand that the above-mentioned modules or steps of the present invention can be implemented by a general-purpose computer device. Optionally, they can be implemented by program codes executable by a computing device, so that they can be stored in a storage device and executed by the computing device, or they can be separately fabricated into individual integrated circuit modules, or multiple modules or steps among them can be fabricated into a single integrated circuit module to implement. The present invention is not limited to any specific combination of hardware and software.

[0093] Although the specific implementation manner of the present invention has been described above in conjunction with the drawings, it is not a limitation to the protection scope of the present invention. Those skilled in the art should understand that on the basis of the technical solution of the present invention, various modifications or deformations that can be made by those skilled in the art without creative labor are still within the protection scope of the present invention.

Claims

1. A method for controlling fuel cell voltage under power grid disturbance, characterized in that: include: Based on the power grid disturbance detection component, the power grid operation status is detected in real time, and whether there is a power grid disturbance under low voltage ride through is determined according to the power grid operation status; When there is a grid disturbance, a differential tracker is used to track and filter the voltage in the current state, and the uncertainty factors of the fuel cell are observed based on the disturbance observer; then, the results obtained by the differential tracker and the disturbance observer are simultaneously input into the nonlinear error feedback compensator to determine the reaction gas compensation amount for inputting into the fuel cell; The excess coefficient of the reaction gas and the circulation rate of the reaction gas are adjusted according to the obtained reaction gas compensation amount to restore the voltage to stability, thereby achieving voltage control of the fuel cell.

2. A fuel cell voltage control method under power grid disturbance as claimed in claim 1, characterized in that: Judging whether there is a grid disturbance under low voltage ride through according to the grid operation status includes: when the phase-to-phase voltage between any two phases of the three-phase electricity of the grid is lower than a preset first phase-to-phase voltage threshold, it is considered that there is a grid disturbance under low voltage ride through.

3. A fuel cell voltage control method under power grid disturbance as claimed in claim 1, characterized in that: The differential tracker is expressed as: u r (t+1) and u r (t) represents the pre-tracking voltage of the differential tracker at time t+1 and time t, respectively. and Respectively represent the pre-tracking voltage u r (t+1) and u r The derivative of (t), T d represents the sampling period, and fhan(t) represents the fastest comprehensive function.

4. A fuel cell voltage control method under power grid disturbance as claimed in claim 1, characterized in that: The uncertainty factors of the fuel cell are observed based on a disturbance observer, wherein the uncertainty factors include load current disturbance, ambient temperature disturbance and reaction gas flow change in the fuel cell.

5. The method for controlling fuel cell voltage under power grid disturbance according to claim 1, characterized in that: The nonlinear error feedback compensator generates a reaction gas compensation amount for inputting into a fuel cell based on a built-in nonlinear feedback function and a proportional-differential control parameter.

6. A fuel cell voltage control method under power grid disturbance as claimed in claim 1, characterized in that: The reaction gas excess coefficient and the reaction gas circulation rate are adjusted according to the obtained reaction gas compensation amount. Specifically, the obtained reaction gas compensation amount and the reaction gas amount actually introduced into the fuel cell in the previous state are taken as the total reaction gas input amount and input into the fuel cell together; the reaction gas excess coefficient and the reaction gas circulation rate are increased by increasing the reaction gas input amount, thereby increasing the voltage.

7. A fuel cell voltage control system under power grid disturbance, characterized in that: include: A fuel cell stack, a power grid disturbance detection component, a first control component and a second control component; wherein the first control component is composed of a differential tracker, a disturbance observer and a nonlinear error feedback compensator; A power grid disturbance detection component is configured to: detect the power grid operation status in real time, and determine whether there is a power grid disturbance under low voltage ride through according to the power grid operation status; The first control component is configured to: when there is a grid disturbance, use a differential tracker to track and filter the voltage in the current state, and observe the uncertainty factor of the fuel cell based on the disturbance observer; Subsequently, the results obtained by the differential tracker and the disturbance observer are simultaneously input into the nonlinear error feedback compensator to determine the reaction gas compensation amount for inputting into the fuel cell; The second control component is configured to adjust the reaction gas excess coefficient and the reaction gas circulation rate according to the obtained reaction gas compensation amount to restore the voltage to stability, thereby achieving voltage control of the fuel cell.

8. A fuel cell voltage control system under power grid disturbance as claimed in claim 7, characterized in that: include: The second control component includes an air compressor and a circulation pump; wherein the air compressor is used to adjust the excess coefficient of the reaction gas by adjusting the input amount of the reaction gas, and the circulation pump is used to adjust the circulation rate of the reaction gas.

9. A fuel cell voltage control system under power grid disturbance according to any one of claims 7 to 8, characterized in that: The first port of the air compressor and the second port of the circulation pump are respectively connected to the cathode inlet and cathode outlet of the fuel cell stack, and at the same time, the second port of the air compressor and the first port of the circulation pump are connected; the third port of the air compressor and the third port of the circulation pump are both connected to the second control component, and the other end interface of the second control component is connected to the power grid disturbance detection component, and the other end of the power grid disturbance detection component is connected to the power grid.

10. A fuel cell voltage control system under power grid disturbance as claimed in claim 9, characterized in that: The power grid disturbance detection component includes a first acquisition device, a second acquisition device and a third acquisition device, which are used to directly acquire the voltage signal of the connected power grid so as to detect the operation status of the power grid in real time.

Images