A coordinated control system for multiphase hydrogen fuel flow and pressure

Abstract

The present application provides a multiphase hydrogen fuel flow and pressure coordinated control system, which belongs to the field of aviation engine technology, including a liquid hydrogen tank, a liquid hydrogen pump, a heat exchanger, a pressure regulating valve, a regulating valve, a stop valve, a sensor and an engine main controller, the engine main controller receives engine status feedback and outputs a hydrogen fuel mass flow instruction; it also includes a pressure regulating valve outlet pressure instruction calculation module and a pressure regulating valve pressure closed-loop control module between the pressure regulating valve and the engine, a liquid hydrogen pump outlet pressure instruction calculation module and a liquid hydrogen pump outlet pressure compensation control module between the liquid hydrogen pump and the engine, and a regulating valve outlet flow advance correction control module between the regulating valve and the engine; the present application scheme coordinates the liquid hydrogen pump speed, the pressure regulating valve opening area, and the regulating valve opening area to achieve dynamic matching of flow and pressure under non-steady working conditions of the hydrogen fuel regulation system, thereby improving the dynamic response performance of flow control of the hydrogen fuel regulation system.

Description

Technical Field

[0001] The present application relates to the field of aviation engine technology, and in particular to a multiphase hydrogen fuel flow and pressure coordinated control system. Background Art

[0002] Hydrogen-fired turbine aircraft engines use hydrogen as fuel. To simultaneously meet the requirements of reducing the size of the aircraft and improving combustion efficiency, liquid hydrogen storage and gaseous hydrogen combustion solutions are the best choices. Therefore, liquid hydrogen phase, gaseous hydrogen phase and liquid-gas conversion process must exist in the hydrogen fuel regulation system.

[0003] The hydrogen fuel regulation system involves multiple controlled objects such as liquid hydrogen pumps, pressure regulating valves, and regulating valves. The complex characteristics of the liquid phase, gas phase, and liquid-gas conversion process of hydrogen fuel, as well as the coordinated work between multiple controlled objects, all pose huge challenges to the control performance of the hydrogen fuel regulation system. Specifically, the following technical issues are involved: 1. The hydrogen fuel regulation system has liquid hydrogen phase, gas hydrogen phase, and liquid-gas conversion, which are affected by multiple controlled objects at the same time. It is difficult to match the flow and pressure under non-stationary conditions. 2. The outlet flow of the liquid hydrogen pump needs to meet the dynamic supply needs of the hydrogen fuel regulation system. At the same time, the liquid hydrogen pump is the main pressure source of the system. It is necessary to ensure stable pressure to prevent overpressure and loss of pressure. It is difficult to take both into account. 3. Gaseous hydrogen is compressible, and there is a certain inertia in the flow and pressure, which has a great impact on the dynamic control performance, resulting in a long transient response time for hydrogen-fired turbine aircraft engines. Summary of the Invention

[0004] In view of this, an embodiment of the present application provides a multiphase hydrogen fuel flow and pressure coordinated control system, which realizes rapid and precise adjustment of the outlet flow and pressure of the hydrogen fuel regulation system through coordinated control of the liquid hydrogen pump speed, the opening area of ​​the pressure regulating valve, and the opening area of ​​the regulating valve, thereby meeting the working requirements of the combustion chamber of the hydrogen-fired turbine aircraft engine.

[0005] An embodiment of the present application provides a multiphase hydrogen fuel flow and pressure coordinated control system, the system includes a liquid hydrogen tank, a liquid hydrogen pump, a heat exchanger, a pressure regulating valve, a regulating valve and a shut-off valve connected in sequence, the hydrogen fuel is delivered to the engine after passing through the shut-off valve, and also includes a sensor and an engine main controller, the engine main controller is used to receive engine status feedback and output a hydrogen fuel mass flow instruction; the hydrogen fuel is delivered to the engine after passing through the shut-off valve; a pressure regulating valve outlet pressure instruction calculation module and a pressure regulating valve pressure closed-loop control module are provided between the pressure regulating valve and the engine, the input end of the pressure regulating valve outlet pressure instruction calculation module is connected to the engine, and the output end of the pressure regulating valve outlet pressure instruction calculation module is connected to the pressure regulating valve pressure closed-loop control module The input end of the block is connected, and the output end of the pressure regulating valve pressure closed-loop control module is connected to the pressure regulating valve; a liquid hydrogen pump outlet pressure instruction calculation module and a liquid hydrogen pump outlet pressure compensation control module are provided between the liquid hydrogen pump and the engine, the input end of the liquid hydrogen pump outlet pressure instruction calculation module is connected to the output end of the pressure regulating valve outlet pressure instruction calculation module and the output end of the engine main controller, and the output end of the liquid hydrogen pump outlet pressure instruction calculation module is connected to the liquid hydrogen pump; a regulating valve outlet flow advance correction control module is provided between the regulating valve and the engine, the input end of the regulating valve outlet flow advance correction control module is connected to the output end of the engine main controller, and the output end of the regulating valve outlet flow advance correction control module is connected to the regulating valve.

[0006] According to a specific implementation of an embodiment of the present application, the pressure regulating valve outlet pressure instruction calculation module includes a shut-off valve, a fuel manifold pressure loss estimation submodule and a sonic flow pressure drop estimation submodule.

[0007] According to a specific implementation of the embodiment of the present application, the pressure regulating valve outlet pressure instruction calculation module outputs the pressure regulating valve outlet pressure instruction, and the calculation formula of the pressure regulating valve outlet pressure instruction is:

[0008] ,

[0009] in, is the outlet pressure command of the pressure regulating valve, is the feedback value of the engine compressor outlet pressure sensor, is the maximum pressure drop of the stop valve, is the maximum pressure drop of the fuel main, and Calculated by the cut-off valve and fuel main pressure loss estimation submodule, is the gas-hydrogen critical pressure ratio, Calculated by the sonic flow pressure drop estimation submodule, It is the margin of the outlet pressure of the pressure regulating valve.

[0010] According to a specific implementation of the embodiment of the present application, the pressure closed-loop control module of the pressure stabilizing valve adopts PI control.

[0011] According to a specific implementation of the embodiment of the present application, the pressure regulating valve pressure closed-loop control module outputs a pressure regulating valve opening area instruction. The expression of the pressure regulating valve opening area instruction is:

[0012] ,

[0013] in, Indicates the pull-type transformation of the opening area instruction of the pressure regulating valve, is the transfer function of the PI controller, k i Indicates the integral gain coefficient of the PI controller, k p represents the proportional gain coefficient of the PI controller, s is the complex variable generated by the Laplace transform process, express The Laplace transform of , It is the feedback value of the pressure sensor at the outlet of the pressure regulating valve.

[0014] According to a specific implementation of an embodiment of the present application, the liquid hydrogen pump outlet pressure instruction calculation module includes a heat exchanger and a flow channel pressure loss estimation submodule. The liquid hydrogen pump outlet pressure instruction calculation module outputs a liquid hydrogen pump outlet pressure instruction. The calculation formula of the liquid hydrogen pump outlet pressure instruction is:

[0015] ,

[0016] in, is the liquid hydrogen pump outlet pressure instruction, is the working pressure drop of the pressure regulating valve, is the maximum pressure drop of the heat exchanger, and Calculated by the heat exchanger and flow channel pressure loss estimation submodule, is the margin of the liquid hydrogen pump outlet pressure.

[0017] According to a specific implementation of the embodiment of the present application, the liquid hydrogen pump outlet pressure compensation control module outputs a liquid hydrogen pump correction speed instruction, and the calculation formula of the liquid hydrogen pump correction speed instruction is:

[0018] ,

[0019] ,

[0020] ,

[0021] in, Correct the speed command for the liquid hydrogen pump, is a constant gain, is the feedback value of the liquid hydrogen pump outlet pressure sensor, is the liquid hydrogen pump speed instruction, is the volumetric efficiency of the liquid hydrogen pump, is the pumped volume of each cavity of the liquid hydrogen pump when it rotates one circle, is the number of cavities per revolution of the liquid hydrogen pump, is the density of liquid hydrogen, is the liquid hydrogen pump outlet flow instruction, It is the flow control instruction of the regulating valve outlet and the hydrogen fuel mass flow instruction .

[0022] According to a specific implementation of the embodiment of the present application, the regulating valve outlet flow advance correction control module includes a flow opening mapping submodule and an advance correction submodule.

[0023] According to a specific implementation of the embodiment of the present application, the flow opening mapping submodule outputs a regulating valve opening area instruction, and the calculation formula of the regulating valve opening area instruction is:

[0024] ,

[0025] in, To regulate the valve opening area instruction, It is the flow control instruction of the regulating valve outlet. is the feedback value of the regulating valve inlet temperature sensor, is the feedback value of the regulating valve inlet pressure sensor, is the gas constant, is the gas hydrogen adiabatic index, It is the ratio of the outlet and inlet pressures of the throttle under the condition of gas-hydrogen sonic velocity.

[0026] According to a specific implementation of the embodiment of the present application, the lead correction submodule outputs a corrected regulating valve opening area instruction. The expression of the corrected regulating valve opening area instruction is:

[0027] ,

[0028] , ,

[0029] Among them, A mv,ref_cor is the corrected control valve opening area instruction, G mv is the transfer function, a and b are the coefficients in the transfer function, and s is a complex variable.

[0030] Beneficial effects:

[0031] The multiphase hydrogen fuel flow and pressure coordinated control system in the embodiment of the present application collaboratively considers the liquid hydrogen pump speed, the pressure regulating valve opening area, and the regulating valve opening area to achieve dynamic matching of flow and pressure under non-stationary working conditions of the hydrogen fuel regulation system; adopts the outlet pressure compensation technology under the liquid hydrogen pump flow open-loop control, while taking into account the liquid hydrogen pump outlet flow and pressure control problems; adopts the regulating valve outlet flow advance correction control technology based on sonic throttling to improve the dynamic response performance of the hydrogen fuel regulation system flow control. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0033] Figure 1 A schematic diagram of the structure of a hydrogen fuel regulating system according to an embodiment of the present invention;

[0034] Figure 2 2. A schematic diagram of a multiphase hydrogen fuel flow and pressure coordinated control system according to an embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of a liquid hydrogen pump outlet pressure compensation control module according to an embodiment of the present invention;

[0036] Figure 4 2. It is a schematic diagram of a control module for regulating valve outlet flow advance correction according to an embodiment of the present invention;

[0037] Figure 5 FIG. 4 is a schematic diagram of a closed-loop pressure control module for a pressure regulating valve according to an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0039] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the features in the following embodiments and embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of this application.

[0040] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on this application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement an apparatus and / or practice a method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this apparatus and / or practice this method.

[0041] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The illustrations only show components related to the present application and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0042] Additionally, in the following description, specific details are provided to provide a thorough understanding of the examples. However, one skilled in the art will appreciate that the aspects described can be practiced without these specific details.

[0043] The present application embodiment provides a multiphase hydrogen fuel flow and pressure coordinated control system. Figures 1 to 5 Provide a detailed description.

[0044] In one embodiment, referring to Figure 1 and Figure 2, provides a multiphase hydrogen fuel flow and pressure coordinated control system, the system includes a liquid hydrogen tank, a liquid hydrogen pump, a heat exchanger, a pressure regulating valve, a regulating valve and a shut-off valve connected in sequence, the hydrogen fuel is delivered to the engine after passing through the shut-off valve, and also includes a sensor and an engine main controller, the engine main controller is used to receive engine status feedback and output a hydrogen fuel mass flow instruction; the hydrogen fuel is delivered to the engine after passing through the shut-off valve; a pressure regulating valve outlet pressure instruction calculation module and a pressure regulating valve pressure closed-loop control module are provided between the pressure regulating valve and the engine, the input end of the pressure regulating valve outlet pressure instruction calculation module is connected to the engine, and the output end of the pressure regulating valve outlet pressure instruction calculation module is connected to the pressure regulating valve pressure closed-loop control module The input end is connected, and the output end of the pressure regulating valve pressure closed-loop control module is connected to the pressure regulating valve; a liquid hydrogen pump outlet pressure instruction calculation module and a liquid hydrogen pump outlet pressure compensation control module are provided between the liquid hydrogen pump and the engine, the input end of the liquid hydrogen pump outlet pressure instruction calculation module is connected to the output end of the pressure regulating valve outlet pressure instruction calculation module and the output end of the engine main controller, and the output end of the liquid hydrogen pump outlet pressure instruction calculation module is connected to the liquid hydrogen pump; a regulating valve outlet flow advance correction control module is provided between the regulating valve and the engine, the input end of the regulating valve outlet flow advance correction control module is connected to the output end of the engine main controller, and the output end of the regulating valve outlet flow advance correction control module is connected to the regulating valve.

[0045] This embodiment proposes a liquid-gas multiphase hydrogen fuel flow / pressure coordinated control technology for a hydrogen fuel regulating system for a hydrogen-fired turbine aircraft engine. By coordinatedly controlling the liquid hydrogen pump speed, the opening area of ​​the pressure regulating valve, and the opening area of ​​the regulating valve, rapid and precise regulation of the hydrogen fuel regulating system outlet flow and pressure is achieved to meet the operating requirements of the hydrogen-fired turbine aircraft engine combustion chamber. Specifically, it includes:

[0046] On-demand adjustment of hydrogen fuel flow and pressure: Dynamically adjust the hydrogen fuel flow and pressure according to the combustion chamber operating conditions of the hydrogen-fired turbine aircraft engine during the transient state, and accurately supply hydrogen fuel that meets the demand;

[0047] Dynamic matching of flow rate / pressure under non-stable working conditions of hydrogen fuel regulating system: There are multiple key sections in the hydrogen fuel regulating system (including the liquid hydrogen pump outlet section, the pressure regulating valve outlet section, and the regulating valve outlet section) to realize the functions of liquid hydrogen supply, gas hydrogen pressure regulation, and gas hydrogen flow regulation. The flow matching of each section is the key to ensure the stability of the hydrogen fuel regulating system. The pressure of the hydrogen fuel regulating system is transmitted step by step from the rear stage (combustion chamber fuel inlet) to the forward stage (liquid hydrogen pump outlet). The pressure matching of each stage is the key to achieve stable supply of hydrogen fuel. The control system proposed in this embodiment satisfies pressure matching while ensuring flow matching;

[0048] Improving the dynamic response performance of hydrogen fuel flow regulation: Gas hydrogen is compressible, and changes in flow and pressure have a certain inertia, which has a significant impact on control performance. The control system proposed in this embodiment achieves improved dynamic performance of flow regulation under the condition of sonic throttling of the control valve.

[0049] In specific implementation, the schematic diagram of the hydrogen fuel regulation system structure is as follows: Figure 1 As shown, the liquid hydrogen tank can be approximated as a constant-pressure liquid hydrogen source. The liquid hydrogen is pressurized by a liquid hydrogen pump and enters the heat exchanger. After the liquid hydrogen is heated in the heat exchanger, it changes into gaseous hydrogen and enters the pressure regulating valve. The gaseous hydrogen flows to the regulating valve after being throttled by the pressure regulating valve and finally flows to the outlet. The function of the hydrogen fuel regulating system is to output hydrogen fuel of specified flow and pressure to the engine combustion chamber.

[0050] Since the transportation process involves the influence of hydrogen fuel liquid-gas phase change and gas hydrogen compressibility, in order to realize the function of the hydrogen fuel regulation system, the mutual cooperation of the liquid hydrogen pump, the pressure regulating valve, and the regulating valve is required. The controlled variables in the hydrogen fuel regulation system include: liquid hydrogen pump speed, pressure regulating valve opening area, and regulating valve opening area. The liquid hydrogen pump is responsible for providing sufficient fuel pressure to counteract the combustion chamber back pressure and pipeline pressure loss, the pressure regulating valve is responsible for ensuring the stability of the regulating valve inlet pressure, and the regulating valve is responsible for regulating and metering the hydrogen fuel mass flow rate. For the hydrogen fuel regulation system, which is a multi-variable controlled object, the hydrogen fuel regulation system flow / pressure collaborative control architecture proposed in the present invention is as follows: Figure 2 As shown, the hydrogen fuel mass flow command The output is calculated by the engine main controller and is also used to control the flow control instruction of the regulating valve outlet. and liquid hydrogen pump outlet flow control instructions :

[0051] .

[0052] In one embodiment, the pressure regulating valve outlet pressure command calculation module includes a shut-off valve, a fuel manifold pressure loss estimation submodule, and a sonic flow pressure drop estimation submodule.

[0053] Furthermore, the pressure regulating valve outlet pressure instruction calculation module outputs the pressure regulating valve outlet pressure instruction, and the calculation formula of the pressure regulating valve outlet pressure instruction is:

[0054] ,

[0055] in, is the outlet pressure command of the pressure regulating valve, is the feedback value of the engine compressor outlet pressure sensor, is the maximum pressure drop of the stop valve, is the maximum pressure drop of the fuel main, and Calculated by the cut-off valve and fuel main pressure loss estimation submodule, is the gas-hydrogen critical pressure ratio, Calculated by the sonic flow pressure drop estimation submodule, It is the margin of the outlet pressure of the pressure regulating valve.

[0056] Furthermore, the liquid hydrogen pump outlet pressure instruction calculation module includes a heat exchanger and a flow channel pressure loss estimation submodule. The liquid hydrogen pump outlet pressure instruction calculation module outputs a liquid hydrogen pump outlet pressure instruction. The calculation formula of the liquid hydrogen pump outlet pressure instruction is:

[0057] ,

[0058] in, is the liquid hydrogen pump outlet pressure instruction, is the working pressure drop of the pressure regulating valve, is the maximum pressure drop of the heat exchanger, and Calculated by the heat exchanger and flow channel pressure loss estimation submodule, is the margin of the liquid hydrogen pump outlet pressure.

[0059] In specific implementation, in order to ensure that the liquid hydrogen pump can generate sufficient pressure to counteract the combustion chamber back pressure and pipeline pressure loss, the liquid hydrogen pump outlet pressure command and the pressure regulating valve outlet pressure command need to be reversed through the compressor outlet pressure feedback. Their mutual relationship can be expressed as:

[0060] ,

[0061] Where, is the feedback value of the engine compressor outlet pressure sensor, is the outlet pressure command of the pressure regulating valve, is the maximum pressure drop of the stop valve, is the maximum pressure drop of the fuel main, corresponding to the stop valve and fuel main pressure loss estimation submodule in Figure 2, is the gas-hydrogen critical pressure ratio, corresponding to the sonic flow pressure drop estimation submodule in Figure 2, The margin of the outlet pressure of the pressure regulating valve can ensure the sonic flow working conditions of the regulating valve. is the liquid hydrogen pump outlet pressure instruction, is the working pressure drop of the pressure regulating valve, is the maximum pressure drop of the heat exchanger, corresponding to Figure 2 Heat exchanger and flow channel pressure loss submodule, This is the margin of the liquid hydrogen pump outlet pressure, which can ensure that the liquid hydrogen pump outlet has sufficient supply pressure.

[0062] In one embodiment, the liquid hydrogen pump outlet pressure compensation control module outputs a liquid hydrogen pump correction speed instruction, and the calculation formula of the liquid hydrogen pump correction speed instruction is:

[0063] ,

[0064] ,

[0065] ,

[0066] in, Correct the speed command for the liquid hydrogen pump, is a constant gain, is the feedback value of the liquid hydrogen pump outlet pressure sensor, is the liquid hydrogen pump speed instruction, is the volumetric efficiency of the liquid hydrogen pump, is the pumped volume of each cavity of the liquid hydrogen pump when it rotates one circle, is the number of cavities per revolution of the liquid hydrogen pump, is the density of liquid hydrogen, is the liquid hydrogen pump outlet flow instruction, It is the flow control instruction of the regulating valve outlet and the hydrogen fuel mass flow instruction .

[0067] When implementing it, refer to Figure 3 The liquid hydrogen pump outlet pressure compensation control module is equipped with an outlet pressure compensation control loop under the liquid hydrogen pump flow open-loop control. The control loop control consists of two parts: flow-speed mapping and pressure error compensation. The liquid hydrogen pump flow-speed open-loop mapping relationship is based on the speed-flow relationship of the liquid hydrogen pump. The speed command is obtained by inversely solving the flow command:

[0068]

[0069] Where, is the outlet flow of the liquid hydrogen pump, is the pumped volume of each cavity of the liquid hydrogen pump when it rotates one circle, is the number of cavities per revolution of the liquid hydrogen pump, is the density of liquid hydrogen, is the liquid hydrogen pump speed, is the volumetric efficiency of the liquid hydrogen pump (the volumetric efficiency is about the liquid hydrogen pump speed and liquid hydrogen pump outlet pressure Volumetric efficiency It is difficult to express accurately using mathematical expressions, and it is necessary to construct a two-dimensional interpolation table through experimental data to approximate the volumetric efficiency.

[0070] The liquid hydrogen pump speed command formula solved inversely based on the speed and flow relationship of the liquid hydrogen pump is:

[0071]

[0072] Where, is the liquid hydrogen pump speed instruction, It is the liquid hydrogen pump outlet flow instruction, and this instruction is equal to the regulating valve outlet flow instruction .

[0073] Since gaseous hydrogen is compressible in the pipeline, the outlet flow of the liquid hydrogen pump does not match the outlet flow of the regulating valve, and there is a certain lag relationship. In addition, the dynamic response of the liquid hydrogen pump speed is slower than the dynamic response of the regulating valve opening. When the liquid hydrogen pump outlet flow control and the regulating valve outlet flow control share the same control instruction, the liquid hydrogen pump outlet pressure is prone to instability. Therefore, on the basis of flow-speed mapping control, liquid hydrogen pump outlet pressure compensation is added to correct the speed instruction to ensure the outlet pressure stability. The corrected speed instruction can be expressed as:

[0074]

[0075] Where, Correct the speed command for the liquid hydrogen pump, is a constant gain, is the liquid hydrogen pump outlet pressure instruction, It is the feedback value of the liquid hydrogen pump outlet pressure sensor.

[0076] The liquid hydrogen pump outlet pressure compensation control module outputs the liquid hydrogen pump correction speed instruction and transmits it to the motor's electric drive for controlling the liquid hydrogen pump.

[0077] In one embodiment, the regulating valve outlet flow advance correction control module includes a flow opening mapping submodule and an advance correction submodule.

[0078] Furthermore, the flow opening mapping submodule outputs a regulating valve opening area instruction, and the calculation formula of the regulating valve opening area instruction is:

[0079] ,

[0080] in, To regulate the valve opening area instruction, It is the flow control instruction of the regulating valve outlet. is the feedback value of the regulating valve inlet temperature sensor, is the feedback value of the regulating valve inlet pressure sensor, is the gas constant, is the gas hydrogen adiabatic index, It is the ratio of the outlet and inlet pressures of the throttle under the condition of gas-hydrogen sonic velocity.

[0081] Furthermore, the advance correction submodule outputs a corrected regulating valve opening area instruction, and the expression of the corrected regulating valve opening area instruction is:

[0082] ,

[0083] , ,

[0084] Among them, A mv,ref_cor is the corrected control valve opening area instruction, G mv is the transfer function, a and b are the coefficients in the transfer function, and s is a complex variable.

[0085] In specific implementation, the control module for regulating valve outlet flow rate advance correction is provided with a regulating valve outlet flow rate advance correction control loop based on sonic throttling, such as Figure 4 As shown in the figure, the outlet flow control of the regulating valve includes two parts: flow-opening mapping and advance correction link.

[0086] The regulating valve realizes the measurement and stable control of hydrogen fuel mass flow based on the sonic throttling prototype. The flow formula of sonic throttling theory is:

[0087]

[0088] Where, To regulate the valve outlet flow, is the regulating valve opening area, is the regulating valve inlet pressure, To regulate the valve inlet temperature, is the gas constant, which is 4157 for hydrogen. is the gas-hydrogen adiabatic index (gas specific heat ratio), It is the ratio of the outlet and inlet pressures of the throttle under the condition of gas-hydrogen sonic velocity, that is, the critical pressure ratio.

[0089] The mapping relationship between the control valve flow rate and the opening degree is based on the flow formula of the sonic flow theory. The control valve opening degree instruction is obtained by reversely solving the flow instruction. The opening degree instruction formula obtained by reversely solving the flow formula of the sonic flow theory is:

[0090]

[0091] Where, is the feedback value of the regulating valve inlet temperature sensor, is the feedback value of the regulating valve inlet pressure sensor, is the flow command of the regulating valve outlet, It is the opening area instruction of the regulating valve.

[0092] Since the inlet pressure of the regulating valve in the formula The pressure will change with the change of the opening instruction, and the change of pressure comes from the integral of the flow, with a certain lag. When the flow instruction needs to be increased, the opening area that needs to be increased is calculated according to the inverse solution formula. As time goes by, the inlet pressure gradually decreases. If you want to maintain the flow instruction, you need to continue to increase the opening area until the balance point of pressure-flow-opening area is reached. Therefore, the dynamic response performance may be affected. In order to alleviate the impact of pressure changes on flow (the actual response is the opening of the control valve), consider using an advance correction link to correct the control valve opening area instruction and improve the dynamic response performance of the control valve outlet flow control. The transfer function of the advance correction link is: , , the s-domain expression of the corrected control valve opening area instruction is: .

[0093] The control valve outlet flow advance correction control module finally outputs the corrected control valve opening area instruction (opening instruction) to the electric drive-motor module, thereby adjusting the opening of the control valve.

[0094] In one embodiment, the pressure closed-loop control module of the pressure stabilizing valve adopts PI control.

[0095] Furthermore, the pressure regulating valve pressure closed-loop control module outputs a pressure regulating valve opening area instruction, and the expression of the pressure regulating valve opening area instruction is:

[0096] ,

[0097] in, Indicates the pull-type transformation of the opening area instruction of the pressure regulating valve, is the transfer function of the PI controller, k i Indicates the integral gain coefficient of the PI controller, k p represents the proportional gain coefficient of the PI controller, and s is the complex variable generated by the Laplace transform process. Its essence is to map the time domain signal to a complex plane with both attenuation and frequency characteristics. express The Laplace transform of , It is the feedback value of the pressure sensor at the outlet of the pressure regulating valve.

[0098] In specific implementation, a pressure regulating valve pressure closed-loop control circuit is set in the pressure regulating valve pressure closed-loop control module, as shown in Figure 5. The pressure regulating valve outlet pressure adopts closed-loop feedback control, and the control error is the difference between the pressure regulating valve outlet pressure command and the pressure sensor feedback. , pressure control adopts PI control, and the relationship between the opening area instruction of the pressure regulating valve and the control error can be expressed by the transfer function as follows: ,in Indicates the pull-type transformation of the opening area instruction of the pressure regulating valve, is the transfer function of the PI controller, express Laplace transform of .

[0099] The embodiments provided by the present invention address the problem of dynamic matching of flow and pressure under non-steady working conditions of the hydrogen fuel regulating system described in Technical Problem 1. The present invention proposes a coordinated control architecture for flow and pressure of the hydrogen fuel regulating system, and allocates coordinated control instructions to the liquid hydrogen pump, pressure regulating valve, and regulating valve to ensure the flow and pressure matching of the system. In response to the problem of balancing the outlet flow and pressure control of the liquid hydrogen pump described in Technical Problem 2, the present invention proposes an outlet pressure compensation technology under open-loop control of the liquid hydrogen pump flow, which maps the flow instruction to the pump motor speed instruction based on the characteristics of the liquid hydrogen pump, calculates the outlet pressure instruction of the liquid hydrogen pump based on the inverse estimation of the flow channel pressure loss, and corrects the error between the outlet pressure instruction of the liquid hydrogen pump and the outlet pressure feedback to obtain a corrected speed instruction, thereby solving the problem of balancing flow and pressure control. In response to the inertia problem of gas hydrogen flow regulation described in Technical Problem 3, the present invention proposes a control valve outlet flow advance correction control technology based on sonic throttling. Based on the sonic throttling flow metering principle, according to the inlet and outlet temperature and pressure feedback of the regulating valve, a flow instruction-regulating valve opening area instruction mapping is constructed, and an advance correction link is added to reduce the influence of pressure inertia and improve the dynamic response performance of flow regulation.

[0100] Therefore, the solution of the present application has the following beneficial effects: synergistically considering the liquid hydrogen pump speed, the opening area of ​​the pressure regulating valve, and the opening area of ​​the control valve, to achieve dynamic matching of the flow and pressure under non-stable working conditions of the hydrogen fuel regulation system; proposing an outlet pressure compensation technology under open-loop control of the liquid hydrogen pump flow, while taking into account the outlet flow and pressure control problems of the liquid hydrogen pump; proposing a control valve outlet flow advance correction control technology based on sonic throttling, thereby improving the dynamic response performance of the flow control of the hydrogen fuel regulation system.

[0101] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A multiphase hydrogen fuel flow and pressure coordinated control system, characterized in that: The system includes a liquid hydrogen tank, a liquid hydrogen pump, a heat exchanger, a pressure regulating valve, a regulating valve and a shut-off valve connected in sequence. The hydrogen fuel is delivered to the engine after passing through the shut-off valve. The system also includes a sensor and an engine main controller. The engine main controller is used to receive engine status feedback and output a hydrogen fuel mass flow instruction. The hydrogen fuel is delivered to the engine after passing through the shut-off valve. A pressure regulating valve outlet pressure instruction calculation module and a pressure regulating valve pressure closed-loop control module are provided between the pressure regulating valve and the engine. The input end of the pressure regulating valve outlet pressure instruction calculation module is connected to the engine, the output end of the pressure regulating valve outlet pressure instruction calculation module is connected to the input end of the pressure regulating valve pressure closed-loop control module, and the output end of the pressure regulating valve pressure closed-loop control module is connected to the pressure regulating valve; a liquid hydrogen pump outlet pressure instruction calculation module and a liquid hydrogen pump outlet pressure compensation control module are provided between the liquid hydrogen pump and the engine. The input end of the liquid hydrogen pump outlet pressure instruction calculation module is connected to the output end of the pressure regulating valve outlet pressure instruction calculation module and the output end of the engine main controller, and the output end of the liquid hydrogen pump outlet pressure instruction calculation module is connected to the liquid hydrogen pump; a regulating valve outlet flow advance correction control module is provided between the regulating valve and the engine. The input end of the regulating valve outlet flow advance correction control module is connected to the output end of the engine main controller, and the output end of the regulating valve outlet flow advance correction control module is connected to the regulating valve.

2. The multiphase hydrogen fuel flow and pressure coordinated control system according to claim 1, characterized in that: The pressure regulating valve outlet pressure instruction calculation module includes a stop valve, a fuel main pipe pressure loss estimation submodule and a sonic flow pressure drop estimation submodule.

3. The multiphase hydrogen fuel flow and pressure coordinated control system according to claim 2, characterized in that: The pressure regulating valve outlet pressure instruction calculation module outputs the pressure regulating valve outlet pressure instruction. The calculation formula of the pressure regulating valve outlet pressure instruction is: ， in, is the outlet pressure command of the pressure regulating valve, is the feedback value of the engine compressor outlet pressure sensor, is the maximum pressure drop of the stop valve, is the maximum pressure drop of the fuel main, and Calculated by the cut-off valve and fuel main pressure loss estimation submodule, is the gas-hydrogen critical pressure ratio, Calculated by the sonic flow pressure drop estimation submodule, It is the margin of the outlet pressure of the pressure regulating valve.

4. The multiphase hydrogen fuel flow and pressure coordinated control system according to claim 3, characterized in that: The pressure closed-loop control module of the pressure stabilizing valve adopts PI control.

5. The multiphase hydrogen fuel flow and pressure coordinated control system according to claim 4, characterized in that: The pressure regulating valve pressure closed-loop control module outputs a pressure regulating valve opening area instruction. The expression of the pressure regulating valve opening area instruction is: ， in, Indicates the pull-type transformation of the opening area instruction of the pressure regulating valve, is the transfer function of the PI controller, k i Indicates the integral gain coefficient of the PI controller, k p represents the proportional gain coefficient of the PI controller, s is the complex variable generated by the Laplace transform process, express The Laplace transform of , It is the feedback value of the pressure sensor at the outlet of the pressure regulating valve.

6. The multiphase hydrogen fuel flow and pressure coordinated control system according to claim 3, characterized in that: The liquid hydrogen pump outlet pressure instruction calculation module includes a heat exchanger and a flow channel pressure loss estimation submodule. The liquid hydrogen pump outlet pressure instruction calculation module outputs a liquid hydrogen pump outlet pressure instruction. The calculation formula of the liquid hydrogen pump outlet pressure instruction is: ， in, is the liquid hydrogen pump outlet pressure instruction, is the working pressure drop of the pressure regulating valve, is the maximum pressure drop of the heat exchanger, and Calculated by the heat exchanger and flow channel pressure loss estimation submodule, is the margin of the liquid hydrogen pump outlet pressure.

7. The multiphase hydrogen fuel flow and pressure coordinated control system according to claim 6, characterized in that: The liquid hydrogen pump outlet pressure compensation control module outputs a liquid hydrogen pump correction speed instruction. The calculation formula of the liquid hydrogen pump correction speed instruction is: ， ， ， in, Correct the speed command for the liquid hydrogen pump, is a constant gain, is the feedback value of the liquid hydrogen pump outlet pressure sensor, is the liquid hydrogen pump speed instruction, is the volumetric efficiency of the liquid hydrogen pump, is the pumped volume of each cavity of the liquid hydrogen pump when it rotates one circle, is the number of cavities per revolution of the liquid hydrogen pump, is the density of liquid hydrogen, is the liquid hydrogen pump outlet flow instruction, It is the flow control instruction of the regulating valve outlet and the hydrogen fuel mass flow instruction .

8. The multiphase hydrogen fuel flow and pressure coordinated control system according to claim 1, characterized in that: The regulating valve outlet flow advance correction control module includes a flow opening mapping submodule and an advance correction submodule.

9. The multiphase hydrogen fuel flow and pressure coordinated control system according to claim 8, characterized in that: The flow opening mapping submodule outputs the regulating valve opening area instruction. The calculation formula of the regulating valve opening area instruction is: ， in, To regulate the valve opening area instruction, It is the flow control instruction of regulating valve outlet. is the feedback value of the regulating valve inlet temperature sensor, is the feedback value of the regulating valve inlet pressure sensor, is the gas constant, is the gas hydrogen adiabatic index, It is the ratio of the outlet and inlet pressures of the throttle under the condition of gas-hydrogen sonic velocity.

10. The multiphase hydrogen fuel flow and pressure coordinated control system according to claim 9, characterized in that: The advance correction submodule outputs a corrected regulating valve opening area instruction. The expression of the corrected regulating valve opening area instruction is: ， ， ， Among them, A mv,ref_cor is the corrected control valve opening area instruction, G mv is the transfer function, a and b are the coefficients in the transfer function, and s is a complex variable.

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