Rapid back pressure regulation and control method and system for fuel cell test

Abstract

The invention discloses a rapid back pressure regulation and control method and system for a high-dynamic-response fuel cell test, belongs to the technical field of hydrogen energy fuel cell tests, and solves the problem of how to design a test method and system capable of rapidly responding and controlling back pressure in a high-precision manner. Therefore, it is ensured that the issued flow is consistent with the control target, the flow of gas flowing into the fuel cell is kept stable when the pressure changes rapidly, the phenomenon of excessive flow or insufficient gas is avoided, and the accuracy and reliability of testing are improved. According to the fuel cell operation condition, the actual mixed gas flow and the mixed gas density are measured, the system flow resistance coefficient is calculated, the system pressure compensation value is calculated according to the system flow resistance coefficient, the system pressure compensation value serves as feedforward of a PID control algorithm for combined control, high-precision and low-overshoot back pressure control is achieved, and therefore the dynamic response speed and stability of the system are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrogen fuel cell testing, and relates to a method and system for quickly regulating back pressure of a fuel cell test with high dynamic response. Background Art

[0002] With the rapid development of the hydrogen energy industry, fuel cell performance testing has become a key technical link. When simulating the rapid load change of fuel cells, the existing test system has large system volume and slow response speed, which leads to distorted test data and cannot accurately reflect the actual working state. Therefore, it is particularly urgent to develop a back pressure control system with rapid pressure increase and decrease capabilities and precise control characteristics.

[0003] In the field of fuel cell testing, especially for automotive fuel cell engine systems, the high dynamics of the test environment and the simulation accuracy of actual working conditions are key indicators for evaluating the performance of the test system. Modern automotive fuel cell systems tend to be compact in design and have a low system volume, which requires them to quickly adjust their working state and achieve efficient energy output and conversion when responding to changes in driving demand, such as transient conditions such as vehicle acceleration, climbing or braking. Therefore, the test system must be able to accurately simulate these fast-changing load conditions to ensure that the performance and reliability of fuel cells in actual applications are accurately evaluated.

[0004] However, traditional fuel cell testing equipment often faces several technical challenges:

[0005] Slow system response: The inherent volume and inertia of large test systems limit the speed of pressure regulation, making it difficult to keep up with rapidly changing load demands in real time, resulting in a gap between simulation results and actual working conditions.

[0006] Insufficient control accuracy: Accurate control of back pressure is crucial to maintaining the optimal working state of the fuel cell, but traditional control systems are prone to overshoot and lag under dynamic conditions, affecting the accuracy and consistency of test data.

[0007] Limitations of simulated operating conditions: Many existing test platforms have difficulty reproducing the rapid pressure fluctuations unique to automotive systems, which limits the exploration and optimization of fuel cell performance limits.

[0008] In view of this, developing a test system that can respond quickly and control back pressure with high precision is of great significance for the research and development and performance verification of fuel cells, especially automotive fuel cells. Summary of the invention

[0009] The technical solution of the present invention is used to solve the problem of how to design a testing method and system capable of rapid response and high-precision back pressure control.

[0010] The present invention solves the above technical problems through the following technical solutions:

[0011] The present invention provides a method for quickly controlling back pressure of a fuel cell test, comprising the following steps:

[0012] Step 1: Perform flow compensation according to the system volume, back pressure change rate and flow compensation coefficient to ensure that the sent flow is consistent with the control target;

[0013] Step 2: According to the operating conditions of the fuel cell, measure the actual mixed gas flow rate and the mixed gas density, calculate the system flow resistance coefficient, and thus evaluate the system flow resistance;

[0014] Step 3: Calculate the system pressure compensation value according to the system flow resistance coefficient and use it as the feedforward of the PID control algorithm to achieve high-precision and low-overshoot back pressure control.

[0015] Furthermore, the flow compensation formula described in step 1 is as follows:

[0016] Q 下发 =Q 目标 +△P*V*K (1)

[0017] Among them, Q 下发 Indicates the delivered traffic, in NL / min; Q 目标 It indicates the set target flow rate in NL / min; △P indicates the back pressure change rate in bar(g); V indicates the system volume in L; K indicates the flow compensation coefficient.

[0018] Furthermore, the calculation formula of the system flow resistance coefficient described in step 2 is as follows:

[0019]

[0020] Where Kv is the system flow resistance coefficient, T2 is the inlet temperature of the measured stack, T3 is the outlet temperature of the measured stack, ρ 混合 is the density of the mixed gas at the inlet of the stack, P2 is the inlet pressure of the stack under test, P3 is the outlet pressure of the stack under test, Q 实际 is the actual mixed gas flow rate at the stack inlet, is the water vapor partial pressure, is the water vapor density, ρ gas is the density of a given gas.

[0021] Furthermore, the calculation formula of the system pressure compensation value described in step 3 is as follows:

[0022]

[0023] Among them, ΔP 计算is the system pressure compensation value.

[0024] The present invention also provides a fuel cell test rapid back pressure control system, comprising: a flow control unit (1), a first temperature sensor (2), a first pressure sensor (3), a system component (4), a second temperature sensor (5), a second pressure sensor (6), a third temperature sensor (7), a third pressure sensor (8), a back pressure control unit (9), and a control unit (10); the inlet of the flow control unit (1) is sealedly connected to the gas inlet, the outlet of the flow control unit (1) is sealedly connected to the inlet of the system component (4) via a pipeline, and the first temperature sensor (2) and the first pressure sensor (3) are arranged on the pipeline between the flow control unit (1) and the system component (4). The outlet of the system component (4) is sealedly connected to the inlet of the fuel cell under test via a pipeline, a second temperature sensor (5) and a second pressure sensor (6) are arranged on the pipeline between the system component (4) and the fuel cell under test, the outlet of the fuel cell under test is sealedly connected to the inlet of the back pressure control unit (9) via a pipeline, and a third temperature sensor (7) and a third pressure sensor (8) are arranged on the pipeline between the fuel cell under test and the back pressure control unit (9); the control unit (10) outputs a control instruction according to the above-mentioned fuel cell test rapid back pressure regulation method, and the control instruction is transmitted to the flow control unit (1) and the back pressure control unit (9) for flow control and back pressure control.

[0025] The present invention also provides an electronic device, including a memory and a processor, wherein the memory is used to store a program that supports the processor to execute the above-mentioned fuel cell test rapid back pressure control method, and the processor is configured to execute the program stored in the memory.

[0026] The present invention also provides a storage medium on which a computer program is stored. When the computer program is run by a processor, the steps of the above-mentioned fuel cell test rapid back pressure control method are executed.

[0027] The advantages of the present invention are:

[0028] The present invention performs flow compensation according to the system volume, the back pressure change rate and the flow compensation coefficient, so as to ensure that the sent flow is consistent with the control target, and ensure that the gas flow flowing into the fuel cell remains stable when the pressure changes rapidly, avoids overflow or underflow, and improves the accuracy and reliability of the test; according to the operating conditions of the fuel cell, the actual mixed gas flow and the mixed gas density are measured, the system flow resistance coefficient is calculated, and the system pressure compensation value is calculated according to the system flow resistance coefficient. It is used as the feedforward of the PID control algorithm for joint control, and high-precision low-overshoot backpressure control is achieved, thereby improving the dynamic response speed and stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a flow chart of a method for rapid back pressure control of a fuel cell test according to a first embodiment of the present invention;

[0030] Figure 2 is a structural diagram of a rapid back pressure control system for fuel cell testing according to a first embodiment of the present invention;

[0031] Figure 3 This is a test result diagram of a rapid pressure boost test using the rapid back pressure control method for fuel cell testing according to the first embodiment of the present invention;

[0032] Figure 4 This is a test result diagram of a multi-loop combined rapid back pressure test using the rapid back pressure control method for fuel cell testing according to the first embodiment of the present invention;

[0033] Figure 5 It is a test result diagram of different pressure control performance tests using the fuel cell test rapid back pressure regulation method of Example 1 of the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments:

[0036] Embodiment 1

[0037] like Figure 1 As shown, this embodiment provides a method for rapid back pressure control of a fuel cell test, comprising the following steps:

[0038] 1. Flow compensation

[0039] Since the pipes, temperature, humidity, pressure and other control devices in the test system have a certain volume, the pressure in the chamber will change during the system pressure change, causing the gas volume stored in the system to change with the pressure, which in turn causes the measured flow to change, resulting in overflow or flow stagnation and lack of gas. Therefore, flow compensation is required based on the system volume, back pressure change rate and flow compensation coefficient to ensure that the measured flow is consistent with the control target. The flow compensation method is as follows:

[0040] Q 下发 =Q 目标 +△P*V*K (1)

[0041] Among them, Q 下发 Indicates the delivered traffic, in NL / min; Q 目标 It represents the set target flow rate in NL / min; △P represents the back pressure change rate in bar(g); V represents the system volume in L; K represents the flow compensation coefficient, which is generally between 0.5 and 2.

[0042] 2. System flow resistance coefficient

[0043] For fuel cell testing, during the back pressure regulation process, since the system volume changes with the back pressure regulation, flow compensation and operating conditions, the gas flow through the fuel cell stack of the device under test will also change, causing the fuel cell flow resistance to change dynamically. In order to achieve more accurate back pressure control, a system flow resistance evaluation is required. Since the fuel cell is operating in a high humidity state, according to the operating conditions of the fuel cell, the actual mixed gas flow rate and mixed gas density are measured, and the system flow resistance coefficient is calculated to evaluate the system flow resistance. The calculation formula of the system flow resistance coefficient is as follows:

[0044]

[0045] Where Kv is the system flow resistance coefficient, T2 is the inlet temperature of the measured stack, T3 is the outlet temperature of the measured stack, ρ 混合 is the density of the mixed gas at the inlet of the stack, P2 is the inlet pressure of the stack under test, P3 is the outlet pressure of the stack under test, Q 实际 is the actual mixed gas flow rate at the stack inlet, is the water vapor partial pressure, is the water vapor density, ρ gas is the density of a given gas.

[0046] 3. Pressure feedforward compensation

[0047] During the back pressure control process, due to the influence of parameter dynamics, there is a certain deviation in the pressure compensation calculation value. By calculating the pressure compensation value and using it as the feedforward of the PID control algorithm, high-precision and low overshoot back pressure control can be achieved. The calculation formula of the system pressure compensation value is as follows:

[0048]

[0049] Among them, ΔP 计算 is the system pressure compensation value.

[0050] Embodiment 2

[0051] like Figure 2As shown, this embodiment provides a fuel cell test rapid back pressure control system, comprising: a flow control unit (1), a first temperature sensor (2), a first pressure sensor (3), a system component (4), a second temperature sensor (5), a second pressure sensor (6), a third temperature sensor (7), a third pressure sensor (8), a back pressure control unit (9), and a control unit (10).

[0052] The inlet of the flow control unit (1) is sealedly connected to the gas inlet, the outlet of the flow control unit (1) is sealedly connected to the inlet of the system component (4) through a pipeline, a first temperature sensor (2) and a first pressure sensor (3) are arranged on the pipeline between the flow control unit (1) and the system component (4), the outlet of the system component (4) is sealedly connected to the inlet of the fuel cell under test through a pipeline, a second temperature sensor (5) and a second pressure sensor (6) are arranged on the pipeline between the system component (4) and the fuel cell under test, the outlet of the fuel cell under test is sealedly connected to the inlet of the back pressure control unit (9) through a pipeline, and a third temperature sensor (7) and a third pressure sensor (8) are arranged on the pipeline between the fuel cell under test and the back pressure control unit (9).

[0053] The flow control unit (1) is used for system flow control; the system component (4) is used for regulating and measuring the temperature, humidity and dew point parameters of the test system, and transmitting the measurement information to the control unit (10); the first temperature sensor (2) and the first pressure sensor (3) are used for monitoring the inlet pressure and temperature of the system component (4), and transmitting the monitoring information to the control unit (10); the second temperature sensor (5) and the second pressure sensor (6) are used for monitoring the inlet pressure and temperature of the fuel cell under test, and transmitting the monitoring information to the control unit (10); the third temperature sensor (7) and the third pressure sensor (8) are used for monitoring the outlet pressure and temperature of the fuel cell under test, and transmitting the monitoring information to the control unit (10); and the back pressure control unit (9) is used for performing system back pressure control.

[0054] The control unit (10) is integrated with the fuel cell test rapid back pressure regulation method described in the first embodiment. The control unit (10) outputs a control instruction according to the fuel cell test rapid back pressure regulation method and transmits it to the flow control unit (1) and the back pressure control unit (9), thereby realizing system flow control and back pressure control.

[0055] Experimental Test:

[0056] (1) Rapid voltage boost test

[0057] like Figure 3As shown, the solid line is the stack inlet pressure, the initial pressure is 40kpa, and the control target pressure is 170kpa. From the test data, a back pressure adjustment rate of 40Kpa / s can be achieved, and the pressure overshoot is small, and the steady state is reached quickly. The dotted line in the figure is the hydrogen supply flow rate, and the method of the present invention is used to perform flow compensation when the pressure changes. From the test data, the method of the present invention can achieve high dynamic and precise pressure control.

[0058] (2) Multi-circuit joint rapid back pressure test

[0059] like Figure 4 As shown, the solid line is the hydrogen inlet pressure of the fuel cell stack, with an initial pressure of 40kpa and a control target pressure of 160kpa; the double-dotted line is the air inlet pressure, with an initial pressure of 30kpa and a control target of 150kpa; the dotted line is the water cooling inlet pressure, with an initial pressure of 30kpa and a control target of 150kpa. It can be seen from the test data that the method of the present invention can achieve highly dynamic coordinated adjustment of multi-system back pressures, and the pressure synergy of each system is strong. While maintaining the rate and synergy, highly dynamic and accurate back pressure control can be achieved.

[0060] (3) Different pressure control performance test

[0061] like Figure 5 As shown, the solid line is the measured value of the hydrogen inlet pressure of the fuel cell stack, and the dotted line is the set value of the inlet pressure. It can be seen from the test data that the control pressure is consistent with the target pressure in each pressure range and reaches stability quickly. This shows that the method of the present invention has strong adaptability and can meet the rapid back pressure adjustment of different pressure ranges.

[0062] Embodiment 3

[0063] An electronic device includes a memory and a processor, wherein the memory is used to store a program that supports the processor to execute the fuel cell test rapid back pressure control method in embodiment 1, and the processor is configured to execute the program stored in the memory.

[0064] Embodiment 4

[0065] A storage medium stores a computer program, which, when executed by a processor, executes the steps of the method for rapid back pressure control of a fuel cell test in Embodiment 1.

[0066] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for rapid back pressure control in fuel cell testing, characterized in that: The following steps are involved: Step 1: Perform flow compensation according to the system volume, back pressure change rate and flow compensation coefficient to ensure that the sent flow is consistent with the control target; Step 2: According to the operating conditions of the fuel cell, measure the actual mixed gas flow rate and the mixed gas density, calculate the system flow resistance coefficient, and thus evaluate the system flow resistance; Step 3: Calculate the system pressure compensation value according to the system flow resistance coefficient and use it as the feedforward of the PID control algorithm to achieve high-precision and low-overshoot back pressure control.

2. The method for rapid back pressure control of fuel cell testing according to claim 1, characterized in that: The formula for flow compensation described in step 1 is as follows: Q 下发 =Q 目标 +△P*V*K (1) Among them, Q 下发 Indicates the delivered traffic, in NL / min; Q 目标 It indicates the set target flow rate in NL / min; △P indicates the back pressure change rate in bar(g); V indicates the system volume in L; K indicates the flow compensation coefficient.

3. The method for rapid back pressure control of fuel cell testing according to claim 2, characterized in that: The calculation formula for the system flow resistance coefficient described in step 2 is as follows: Where Kv is the system flow resistance coefficient, T2 is the inlet temperature of the measured stack, T3 is the outlet temperature of the measured stack, ρ 混合 is the density of the mixed gas at the inlet of the stack, P2 is the inlet pressure of the stack under test, P3 is the outlet pressure of the stack under test, Q 实际 is the actual mixed gas flow rate at the stack inlet, is the water vapor partial pressure, is the water vapor density, ρ gas is the density of a given gas.

4. The method for rapid back pressure control of fuel cell testing according to claim 3, characterized in that: The calculation formula for the system pressure compensation value described in step 3 is as follows: Among them, ΔP 计算 is the system pressure compensation value.

5. A fuel cell test rapid back pressure control system, comprising: A flow control unit (1), a first temperature sensor (2), a first pressure sensor (3), a system component (4), a second temperature sensor (5), a second pressure sensor (6), a third temperature sensor (7), a third pressure sensor (8), a back pressure control unit (9), and a control unit (10); the inlet of the flow control unit (1) is sealedly connected to the gas inlet, the outlet of the flow control unit (1) is sealedly connected to the inlet of the system component (4) via a pipeline, the first temperature sensor (2) and the first pressure sensor (3) are arranged on the pipeline between the flow control unit (1) and the system component (4), the outlet of the system component (4) is connected to the inlet of the fuel cell to be tested A second temperature sensor (5) and a second pressure sensor (6) are arranged on the pipeline between the system component (4) and the fuel cell under test through a pipeline sealing connection, the outlet of the fuel cell under test and the inlet of the back pressure control unit (9) are connected through a pipeline sealing connection, and a third temperature sensor (7) and a third pressure sensor (8) are arranged on the pipeline between the fuel cell under test and the back pressure control unit (9); it is characterized in that the control unit (10) outputs a control instruction according to the fuel cell test rapid back pressure regulation method described in any one of claims 1 to 4, and the control instruction is transmitted to the flow control unit (1) and the back pressure control unit (9) for flow control and back pressure control.

6. An electronic device, comprising a memory and a processor, characterized in that: The memory is used to store a program that supports the processor to execute the fuel cell test rapid back pressure control method according to any one of claims 1 to 4, and the processor is configured to execute the program stored in the memory.

7. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for rapid back pressure regulation of fuel cell testing according to any one of claims 1 to 4 are executed.

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