Method for controlling proportional electromagnetic valve of hydrogen fuel cell

Abstract

The invention discloses a hydrogen fuel cell proportional electromagnetic valve control method which comprises the following steps: acquiring a set value and a feedback value of a controlled target, and calculating a control error; on the basis of the control error, closed-loop control output is obtained through calculation of a closed-loop controller; generating a resonance waveform output through a resonance waveform generator, wherein the resonance waveform output has a resonance frequency, a resonance amplitude value and a resonance waveform parameter which are calibrated in advance; superposing the closed-loop control output and the resonance waveform output to obtain a duty ratio set value of the proportional electromagnetic valve; outputting the duty ratio set value to a proportional electromagnetic valve; wherein the resonant frequency, the resonant amplitude value, the resonant waveform parameter and the PWM driving frequency parameter are determined through a resonant parameter calibration method.

Description

Technical Field

[0001] This invention relates to the field of hydrogen fuel cell technology, and specifically to a method for controlling a proportional solenoid valve in a hydrogen fuel cell. Background Technology

[0002] In industrial flow and pressure control systems, proportional solenoid valves are commonly used as supply components. When a proportional solenoid valve is working, the valve core displacement is proportional to the effective value of the coil current, and there is friction between the valve core and the inner wall. After the valve core current stabilizes for a period of time, the force on the valve core will change from dynamic friction to static friction. When it is necessary to change the valve core position, the valve core current must be significantly increased to overcome the static friction. This process is known as the "viscous effect." The viscous effect will increase the system's hysteresis characteristics and reduce the valve core sensitivity. At the same time, under the hysteresis of the closed-loop control system itself, the valve core will always be in a large stroke. This process will not only lead to instability of the controlled physical quantity, but also accelerate the wear of the valve core. Therefore, it is necessary to introduce a resonant control algorithm into the proportional valve control to keep the valve core in a state of micro-friction to improve the valve control accuracy and the system response speed.

[0003] Currently, in the hydrogen fuel cell industry, the control of proportional solenoid valves typically only models and controls the valve's working mechanism characteristics, such as electromagnetic, mechanical, and fluid properties, while ignoring the inherent defects of the valve core. This leads to a decrease in the reliability of the designed control algorithm after long-term operation. Furthermore, in industrial applications, when selecting resonance parameters, the control effect is often emphasized while the valve core's lifespan is ignored. Therefore, both of the above proportional valve control methods have their advantages and disadvantages, but neither can simultaneously ensure control effectiveness and valve lifespan. Especially in the hydrogen fuel cell industry, proportional valves are expensive. Therefore, this invention addresses the advantages and disadvantages of the above two application scenarios by proposing a hydrogen fuel cell proportional solenoid valve control method. This method not only improves control accuracy but also extends valve core lifespan, while the resonance parameter calibration is simple and the algorithm is easy to implement. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method for controlling a proportional solenoid valve in a hydrogen fuel cell, which aims to overcome at least one related technical problem existing in the background art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: This application provides a method for controlling a proportional solenoid valve in a hydrogen fuel cell, comprising the following steps: Obtain the setpoint and feedback value of the controlled target, and calculate the control error; Based on the control error, the closed-loop control output is calculated by the closed-loop controller. A resonant waveform output is generated by a resonant waveform generator, and the resonant waveform output has a pre-calibrated resonant frequency, resonant amplitude, and resonant waveform parameters. The closed-loop control output is superimposed with the resonant waveform output to obtain the duty cycle setting value of the proportional solenoid valve; The duty cycle setting value is output to the proportional solenoid valve; The resonant frequency, resonant amplitude, resonant waveform, and PWM drive frequency parameters are all determined by the resonant parameter calibration method.

[0006] The core of this application's method lies in superimposing a low-frequency, low-amplitude resonant signal onto the conventional closed-loop control output. This additional signal keeps the valve core in a micro-movement state, thereby avoiding the generation of static friction and fundamentally suppressing the "viscous effect."

[0007] To address the challenge of scientifically selecting resonance parameters, a two-stage resonance parameter calibration method is proposed: first, a reference standard is obtained at low frequencies without resonance; then, the resonance parameters are adjusted at high frequencies to reproduce this reference standard and avoid resonance. In some optional implementations, the resonance parameter calibration method includes PWM drive frequency calibration and resonance parameter calibration, including: Under the first PWM drive frequency and the first duty cycle opening, and the second duty cycle opening, and without superimposed resonance control, the first peak-to-peak value and the second peak-to-peak value of the waveform of the physical quantity measured by the sensor are respectively obtained as reference values. The first PWM drive frequency is a selected frequency within the recommended operating frequency range of the proportional valve.

[0008] If the peak-to-peak value of the waveform of the physical quantity measured by the sensor is significantly less than the first peak-to-peak value when the second PWM driving frequency is higher than the first PWM driving frequency and the duty cycle is the same as the first duty cycle, then the PWM driving frequency calibration is complete.

[0009] Under the second PWM drive frequency and duty cycle opening of the calibrated second duty cycle opening, resonant control is superimposed and the resonant parameters are adjusted until the peak-to-peak value of the waveform of the physical quantity measured by the sensor is comparable to the second peak-to-peak value, and the resonant frequency is set to a frequency far away from the inherent frequency of the fuel cell system.

[0010] In order to achieve effective monitoring at the lowest cost, in some alternative implementations, the waveform of the physical quantity measured by the sensor is a valve core current waveform or a valve core displacement sensor waveform.

[0011] To achieve rapid, accurate, and automated parameter calibration, the resonant parameter calibration method is specified as a multi-step process including obtaining a low-frequency reference, confirming high-frequency attenuation, iteratively searching for resonant parameters, and full-range calibration. In some optional implementations, the resonant parameter calibration method specifically includes the following steps: a) Set the PWM drive frequency to the first PWM drive frequency. fL And measure the proportional valve opening value at the minimum airflow duty cycle. D min The sensor measures the peak-to-peak value of the physical quantity waveform. M L ; b) Measurement at PWM drive frequency of f L Furthermore, the peak-to-peak value of the physical quantity measured by the sensor at a duty cycle of 50% M ppL ; c) Adjust the PWM drive frequency to the second PWM drive frequency. f H The peak-to-peak value of the waveform of the physical quantity measured by the sensor at a duty cycle of 50% is measured. M ppH And confirm that it meets the requirements. M ppH <kM ppL ,in k This is the predetermined amplitude attenuation coefficient; d) Initialize the resonant frequency of the resonant waveform generator. f D With resonance amplitude D step [N]; e) Maintain the PWM drive frequency as f H The PWM duty cycle setting value is the minimum airflow duty cycle opening value. D min By adjusting the resonant frequency f D and the resonance amplitude D step [N], making the peak-to-peak value of the physical quantity measured by the sensor... M pp and M L The difference is within a predetermined error range, while ensuring the resonant frequency. f D Distance from the inherent frequency of the fuel cell system; f) After completing step e), keep the resonant frequency constant, and ensure that the peak-to-peak value of the sensor-measured physical quantity waveform under different PWM duty cycles is no greater than [value missing]. M L .

[0012] To obtain a stable and easily measurable reference, in some alternative implementations, the first PWM drive frequency... f L The lowest value within the recommended operating frequency range for proportional valves.

[0013] In order to create optimal conditions for micro-resonant control while ensuring the normal flow control function of the proportional valve, in some optional embodiments, the second PWM drive frequency is... f H The frequency is above several kilohertz.

[0014] To provide a clear and operable criterion for selecting the high-frequency drive frequency, in some optional embodiments, when the sensor is a displacement sensor, the amplitude attenuation coefficient is... k It is 0.2.

[0015] To provide a flexible and easy-to-implement resonant excitation method, in some alternative implementations, the resonant waveform is a waveform whose periodic integral sum is 0, such as a square wave, a triangular wave, or a sine wave.

[0016] To ensure compatibility with various mainstream control strategies, in some optional embodiments, the closed-loop controller is a PID controller, a fuzzy controller, a model predictive controller, or a robust controller.

[0017] To prevent control command overflow due to signal superposition and to ensure the stability and safety of the control system, in some optional embodiments, after superimposing the closed-loop control output with the resonant waveform output, the obtained duty cycle setting value is subjected to amplitude limiting processing to limit it to the range of 0% to 100%.

[0018] The beneficial effects that the hydrogen fuel cell proportional solenoid valve control method disclosed in this application may bring include, but are not limited to: The hydrogen fuel cell proportional solenoid valve control method of this invention is simple to operate and fast in resonance algorithm calibration, and can be automated by software. At the same time, when selecting parameters, it not only considers the control effect, but also the valve core life and pipeline vibration. Therefore, while improving the valve's service life and system reliability, it can also significantly reduce the valve core hysteresis range and delay, further accelerating the system control accuracy and response speed. In addition, except for the use of current or displacement sensors during calibration, the control process of this invention is implemented entirely in software, without the need for additional sensors and circuits, which can further reduce costs. Attached Figure Description

[0019] Figure 1 Hardware and software diagrams; Figure 2 Schematic diagram of resonant waveforms (square wave on the left, triangular wave on the right); Figure 3 A schematic diagram showing the relationship between resonant amplitude and duty cycle. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The described embodiments are some, but not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0021] The technical solution of this embodiment includes two parts: proportional valve resonance algorithm calibration and proportional valve control algorithm design. For the convenience of the patent description below, the overall hardware and software structure required to implement this patent is described here, such as... Figure 1 As shown, it comprises both software and hardware. The software includes a closed-loop controller, a resonant waveform generator, and a PWM peripheral controller. The hardware includes a proportional solenoid valve, an oscilloscope, sensors, and the controlled physical object (such as pipelines, valves, etc.). Specifically, when the closed-loop enable parameter of the PWM peripheral controller is disabled, the PWM peripheral directly responds to the duty cycle setpoint and PWM frequency setpoint input parameters, without responding to the closed-loop control output. If enabled, it only responds to the PWM frequency setpoint and the closed-loop control output value, without responding to the duty cycle setpoint.

[0022] One aspect of this application is to provide a method for controlling a proportional solenoid valve in a hydrogen fuel cell, comprising the following steps: Obtain the setpoint and feedback value of the controlled target, and calculate the control error; Based on the control error, the closed-loop control output is calculated by the closed-loop controller. A resonant waveform output is generated by a resonant waveform generator, and the resonant waveform output has a pre-calibrated resonant frequency, resonant amplitude, and resonant waveform parameters. The closed-loop control output is superimposed with the resonant waveform output to obtain the duty cycle setting value of the proportional solenoid valve; The duty cycle setting value is output to the proportional solenoid valve; The resonant frequency, resonant amplitude, resonant waveform, and PWM drive frequency parameters are all determined by the resonant parameter calibration method.

[0023] The core of this application's method lies in superimposing a high-frequency, low-amplitude resonant signal onto the conventional closed-loop control output. This additional signal keeps the valve core in a micro-movement state, thereby avoiding the generation of static friction and fundamentally suppressing the "viscous effect."

[0024] To simultaneously improve control accuracy and valve life, the closed-loop control output is superimposed with a pre-calibrated resonant waveform output, enabling the valve core to maintain micro-movement even in steady state. This significantly reduces system hysteresis and delay, improves dynamic response speed, and effectively extends the valve core's service life.

[0025] To address the challenge of scientifically selecting resonance parameters, a two-stage resonance parameter calibration method is proposed: first, a reference standard is obtained at low frequencies without resonance; then, the resonance parameters are adjusted at high frequencies to reproduce this reference standard and avoid resonance. In some optional implementations, the resonance parameter calibration method includes PWM drive frequency calibration and resonance parameter calibration, including: Under the first PWM drive frequency and the first duty cycle opening, and the second duty cycle opening, and without superimposed resonance control, the first peak-to-peak value and the second peak-to-peak value of the waveform of the physical quantity measured by the sensor are respectively obtained as reference values. The first PWM drive frequency is a selected frequency within the recommended operating frequency range of the proportional valve.

[0026] If the peak-to-peak value of the waveform of the physical quantity measured by the sensor is significantly less than the first peak-to-peak value when the second PWM driving frequency is higher than the first PWM driving frequency and the duty cycle is the same as the first duty cycle, then the PWM driving frequency calibration is complete.

[0027] Under the second PWM drive frequency and duty cycle opening of the calibrated second duty cycle opening, resonant control is superimposed and the resonant parameters are adjusted until the peak-to-peak value of the waveform of the physical quantity measured by the sensor is comparable to the second peak-to-peak value, and the resonant frequency is set to a frequency far away from the inherent frequency of the fuel cell system.

[0028] This method ensures that the calibrated parameters can effectively drive the valve core while also taking into account the reliability of the system structure, thus achieving the best balance between control performance and mechanical life.

[0029] This calibration process compares the vibration amplitude of the valve core at different frequencies to find an equivalent minimum resonant excitation that can overcome static friction for the high-frequency operating mode, and ensures that the excitation will not cause resonance in the system structure.

[0030] To achieve effective monitoring at the lowest cost, in some optional implementations, the sensor measures either a valve core current waveform or a valve core displacement waveform. These two signals are easy to acquire and can directly reflect the working state of the valve core. The valve core current indirectly reflects the magnitude of the electromagnetic force, while the valve core displacement directly reflects the actual motion state of the valve core. Both can effectively characterize whether the valve core has overcome static friction and entered a micro-motion state.

[0031] To achieve rapid, accurate, and automated parameter calibration, the resonant parameter calibration method is specified as a multi-step process including obtaining a low-frequency reference, confirming high-frequency attenuation, iteratively searching for resonant parameters, and full-range calibration. In some optional implementations, the resonant parameter calibration method specifically includes the following steps: a) Set the PWM drive frequency to the first PWM drive frequency. f L And measure the proportional valve opening value at the minimum airflow duty cycle. D min The sensor measures the peak-to-peak value of the physical quantity waveform. M L ; b) Measurement at PWM drive frequency of f L Furthermore, the peak-to-peak value of the physical quantity measured by the sensor at a duty cycle of 50% M ppL ; c) Adjust the PWM drive frequency to the second PWM drive frequency. f H The peak-to-peak value of the waveform of the physical quantity measured by the sensor at a duty cycle of 50% is measured. M ppH And confirm that it meets the requirements. M ppH <kM ppL ,in k This is the predetermined amplitude attenuation coefficient; d) Initialize the resonant frequency of the resonant waveform generator. f D With resonance amplitude D step [N]; e) Maintain the PWM drive frequency as f H The duty cycle setting value is the minimum airflow duty cycle opening value. D min By adjusting the resonant frequency f D and the resonance amplitude D step [N], making the peak-to-peak value of the physical quantity measured by the sensor... M PP and M L The difference is within a predetermined error range, while ensuring the resonant frequency. f D Distance from the inherent frequency of the fuel cell system; f) After completing step e), keep the resonant frequency constant, and ensure that the peak-to-peak value of the sensor-measured physical quantity waveform under different PWM duty cycles is no greater than [value missing]. M L .

[0032] This is a systematic, data-driven calibration process. Through specific measurement, comparison, and adjustment steps, it ensures that the resonant excitation precisely engages and maintains the valve core in an ideal fretting friction state at different operating points (duty cycles). The process is clearly defined, highly programmable, and easily automated via software, significantly improving calibration efficiency and consistency.

[0033] In some embodiments, in order to obtain a stable and easily measurable reference, the first PWM drive frequency... f L The lowest recommended frequency within the operating range for the proportional valve is specified. At this frequency, the sensor can capture waveforms with larger amplitudes and more distinct characteristics, providing a reliable basis for comparison in subsequent high-frequency calibration.

[0034] At lower driving frequencies, the fluctuations in the inertial and electromagnetic forces of the valve core are more pronounced, making it easier to observe the complete motion waveform of the valve core and thus obtain a more stable and representative reference peak-to-peak value. M ppL .

[0035] In some embodiments, in order to create optimal conditions for micro-resonant control while ensuring the normal flow control function of the proportional valve, the second PWM drive frequency is... f H The frequency is set to several kilohertz or higher. At this high frequency, the fundamental vibration of the valve core is suppressed, and the superimposed resonant signal can be used more accurately and efficiently to overcome static friction without interfering with the main control function.

[0036] Under high-frequency PWM drive, the valve core, due to its mechanical inertia, cannot make a large-amplitude follow-up movement in time. Its average displacement is determined by the duty cycle, but the vibration amplitude (peak-to-peak value) will be significantly reduced. This provides ideal working conditions for superimposing a small resonant signal to control the micro-motion.

[0037] In some embodiments, to provide a clear and operable high-frequency drive frequency selection criterion, when the sensor is a displacement sensor, the amplitude attenuation coefficient is... k The value is 0.2. This value is an empirical engineering threshold, indicating that when the vibration amplitude of the valve core under high-frequency drive drops to 20% of that under low-frequency drive, the basic vibration of the valve core is considered to be sufficiently suppressed, achieving the ideal state of superimposed resonance control.

[0038] It should be noted that this specific value ensures the objectivity and repeatability of the calibration process. For other types of sensors (such as current sensors), the appropriate value can be determined through evaluation based on their characteristics. k value.

[0039] In some embodiments, to provide a flexible and easily implemented resonant excitation method, the resonant waveform is a square wave, triangular wave, or sine wave, etc., whose periodic integral sum is 0. These periodic waveforms can all provide alternating excitation force, causing the valve core to reciprocate slightly. Square waves and triangular waves are easier to digitally generate with less computation; sine waves are smoother. These equivalent waveform choices allow the invention to be easily implemented on controllers with varying computing capabilities.

[0040] In some embodiments, to ensure compatibility with various mainstream control strategies, the closed-loop controller is a PID controller, fuzzy controller, model predictive controller, or robust controller. Regardless of the advanced control algorithm used, its core function is to calculate the main driving signal (i.e., the closed-loop control output) used to eliminate the error of the controlled variable. This design allows the resonant superposition method of the present invention to be seamlessly integrated into existing or advanced control systems as a universal module, enhancing its applicability.

[0041] To prevent control command overflow due to signal superposition and to ensure the stability and safety of the control system, in some optional embodiments, after superimposing the closed-loop control output with the resonant waveform output, the obtained duty cycle setting value is subjected to amplitude limiting processing to limit it to the range of 0% to 100%.

[0042] Since both the closed-loop control output and the resonant waveform output are dynamically changing, their direct superposition may exceed the effective range acceptable to the PWM generator. Limiting ensures the physical realizability of the output signal. This is a necessary protective step that guarantees the robustness of the control algorithm.

[0043] The technical solution of this application effectively suppresses the viscous effect of the valve core, thereby significantly reducing the hysteresis range and control delay of the proportional valve. This makes the system respond to control commands faster and more accurately, thus improving the control accuracy and stability of key parameters such as hydrogen pressure or flow rate, and optimizing the operating efficiency of the fuel cell stack.

[0044] During the calibration of the resonance parameters, "avoiding pipeline resonance" was clearly taken as the core consideration. By keeping the resonance frequency away from the system's natural frequency, mechanical fatigue or damage that may be caused by resonance was prevented, thus improving the long-term operational reliability of the entire fuel cell system.

[0045] This invention requires no additional hardware sensors or circuits during normal operation. Its core control algorithm is implemented entirely in software, requiring only general-purpose instruments (such as an oscilloscope) during initial calibration. This pure software implementation makes the solution inexpensive and easy to integrate and deploy on existing control system platforms.

[0046] The provided resonance parameter calibration method has clear operation steps, strong logic, and is easy to automate with software, enabling rapid parameter tuning. More importantly, this method simultaneously considers control effect, valve core life, and mechanical structure reliability when selecting parameters, overcoming the shortcomings of existing technologies that often only focus on one aspect, and achieving a comprehensive optimal solution.

[0047] The present application is illustrated in detail below with a specific embodiment: A method for controlling a proportional solenoid valve in a hydrogen fuel cell includes the following steps: Step 1: Set the closed-loop enable input parameter of the PWM peripheral controller to enable, and connect the output DO of the closed-loop controller; Step 2: Obtain the setpoint and feedback value of the controlled target, calculate the current control error, and input it into the controller for calculation to obtain the closed-loop control calculation result D0; the controlled target can be a physical quantity such as flow rate or pressure, and the controller is not limited to PID controller, fuzzy controller, MPC, robust controller, etc. Step 3: Based on the calibration results of the subsequent resonance parameter calibration method, set the resonant frequency, amplitude and waveform parameters of the resonant waveform generator, and obtain the output Dk of the resonant waveform generator; Step 4: Superimpose the closed-loop control calculation results with the output of the resonant waveform generator to obtain the proportional valve duty cycle setting value, and then output it to the proportional valve after limiting it to 0%-100%.

[0048] The method for calibrating the resonance parameters is as follows: Step 1: Set the closed-loop enable input parameter of the PWM peripheral controller to be disabled; Step 2: Obtain the PWM drive frequency (Hz) that provides the best physical control performance for the proportional valve under test at a lower PWM drive frequency and without superimposed resonance control; select the lowest value within the recommended operating frequency range of the proportional valve, denoted as... f L For example, if the recommended operating frequency range for a certain proportional valve is [300, 500] Hz, then 300 Hz is preferred. Step 3: Set the pressure at the front end of the proportional valve to a small fluctuation range, and measure the proportional valve pressure at the PWM drive frequency. f L Below, the minimum airflow duty cycle opening value of the proportional valve. Dmin The peak-to-peak value of the physical quantity waveform is measured using an oscilloscope after the sensor has stabilized, and recorded as follows: M L Preferably, the pressure at the front end of the proportional valve should be set near the maximum value of the valve's working pressure range. For example, if the recommended working pressure range of a proportional valve is [900, 1350] kPa.A, and the pressure stabilization error of the front-end pressure stabilization system is less than 50 kPa.A under the maximum flow rate of the valve, then 1300 kPa.A is preferred as the pressure at the front end of the proportional valve. Step 4: Measure the PWM drive frequency using an oscilloscope. f L At a duty cycle of 50%, the peak-to-peak value of the measured physical quantity waveform of the sensor after stabilization is denoted as... M ppL ; Step 5: Adjust the valve core PWM drive frequency to a high frequency, denoted as... f H The waveform of the sensor measured the physical quantity when the PWM duty cycle was 50% was measured using an oscilloscope, and recorded as follows: M ppH If satisfied M ppH <kM ppL If the PWM drive frequency calibration is successful, then the PWM drive frequency calibration is complete; otherwise, continue increasing the PWM frequency. k The amplitude attenuation coefficient is preferred. f H When the frequency should be above several kilohertz and the sensor is a displacement sensor, it should satisfy the following conditions. M ppH <kM ppL When the sensor is a current sensor, its k It needs to be assessed and determined; Step 6: Set the PWM drive frequency of the PWM peripheral controller to the frequency calibrated in Step 5. f H ; Step 7: Set the PWM duty cycle to the minimum airflow duty cycle opening value. D min resonant waveform generator f D Initial resonance amplitude D step [N] represents a duty cycle of 0%, and the initial resonant frequency is set to 10Hz. The resonant waveform can be a square wave, triangle wave, or sine wave, etc., with a period amplitude integral of 0. Preferably, a square wave or triangle wave is selected, and the preferred waveform is as follows: Figure 2 As shown; Step 8: Initial Resonance AmplitudeD step [N] is 0%. D step [N-1] is 0%, and the resonant amplitude increases by a step of δ%, where D step [N-1] represents the resonance amplitude of the previous test; Step 9: Calculate the next resonance amplitude, satisfying... D step [N]= D step [N-1]+δ, and satisfying D step [N]≤100%; preferably, the resonant amplitude is generally less than 20% duty cycle; Step 10: Measure the resonant amplitude using an oscilloscope. D step Under [N], the peak-to-peak value of the measured physical quantity waveform of the sensor after stabilization is denoted as . M pp ; Step 11: Maintain the resonant amplitude from Step 10 D step [N] remains unchanged, resonant frequency remains unchanged, measurement M pp Simultaneously observe the vibration of the pipelines before and after the proportional valve. If significant vibration occurs in the pipeline, increase the resonant frequency in 1Hz increments and then return to Step 8; otherwise, when a certain D step [N] satisfies M pp ≈M L At that time, the resonant frequency calibration is completed; preferably, the resonant frequency is... f D It should be kept away from the natural frequency of the fuel cell system to prevent resonance in the fuel cell system; Step 12: Keeping the PWM drive frequency and resonant frequency calibrated in Steps 5 and 11 unchanged, measure the PWM duty cycle from... D min Up to 100% and the interval is Each point below corresponds to M pp ,in The PWM duty cycle is measured at intervals, and at each measurement point, the resonant amplitude is adjusted to ensure that it meets the requirements. M pp ≈M L ,like Figure 3 As shown, the resonance amplitude calibration is now complete; note that... Figure 3It simply illustrates a relationship of change, which can be a linear or non-linear curve.

[0049] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for controlling a proportional solenoid valve in a hydrogen fuel cell, characterized in that, Includes the following steps: Obtain the setpoint and feedback value of the controlled target, and calculate the control error; Based on the control error, the closed-loop control output is calculated by the closed-loop controller. A resonant waveform output is generated by a resonant waveform generator, and the resonant waveform output has a pre-calibrated resonant frequency, resonant amplitude, and resonant waveform parameters. The closed-loop control output is superimposed with the resonant waveform output to obtain the duty cycle setting value of the proportional solenoid valve; The duty cycle setting value is output to the proportional solenoid valve; The resonant frequency, resonant amplitude, resonant waveform, and PWM drive frequency parameters are all determined by the resonant parameter calibration method.

2. The method for controlling a proportional solenoid valve in a hydrogen fuel cell according to claim 1, characterized in that, The resonant parameter calibration method includes PWM drive frequency calibration and resonant parameter calibration, including: Under the first PWM drive frequency and the first duty cycle opening, and the second duty cycle opening, and without superimposed resonance control, the first peak-to-peak value and the second peak-to-peak value of the waveform of the physical quantity measured by the sensor are respectively obtained as reference values. The first PWM drive frequency is a selected frequency within the recommended operating frequency range of the proportional valve. If the peak-to-peak value of the waveform of the physical quantity measured by the sensor is less than the first peak-to-peak value when the second PWM driving frequency is higher than the first PWM driving frequency and the duty cycle is the same as the first duty cycle, then the PWM driving frequency calibration is completed. Under the second PWM drive frequency and duty cycle opening of the calibrated second duty cycle opening, resonant control is superimposed and the resonant parameters are adjusted until the peak-to-peak value of the waveform of the physical quantity measured by the sensor is comparable to the second peak-to-peak value, and the resonant frequency is set to a frequency far away from the inherent frequency of the fuel cell system.

3. The method for controlling a proportional solenoid valve in a hydrogen fuel cell according to claim 2, characterized in that, The physical quantity waveform measured by the sensor is either the valve core current waveform or the valve core displacement sensor waveform.

4. The method for controlling a proportional solenoid valve in a hydrogen fuel cell according to claim 2, characterized in that, The resonance parameter calibration method specifically includes the following steps: a) Set the PWM drive frequency to the first PWM drive frequency. f L And measure the proportional valve opening value at the minimum airflow duty cycle. D min The sensor measures the peak-to-peak value of the physical quantity waveform. M L ; b) Measurement at PWM drive frequency of f L Furthermore, the peak-to-peak value of the physical quantity measured by the sensor at a duty cycle of 50% M ppL ; c) Adjust the PWM drive frequency to the second PWM drive frequency. f H The peak-to-peak value of the waveform of the physical quantity measured by the sensor at a duty cycle of 50% is measured. M ppH And confirm that it meets the requirements. M ppH <kM ppL ,in k This is the predetermined amplitude attenuation coefficient; d) Initialize the resonant frequency of the resonant waveform generator. f D With resonance amplitude D step [N]; e) Maintain the PWM drive frequency as f H The duty cycle setting value is the minimum airflow duty cycle opening value. D min By adjusting the resonant frequency f D and the resonance amplitude D step [N], making the peak-to-peak value of the physical quantity measured by the sensor... M pp and M L The difference is within a predetermined error range, while ensuring the resonant frequency. f D Distance from the inherent frequency of the fuel cell system; f) After completing step e), keep the resonant frequency constant and adjust the resonant amplitude at different PWM duty cycles so that the peak-to-peak value of the sensor's measured physical quantity waveform is no greater than [value missing] at each duty cycle. M L .

5. The method for controlling a proportional solenoid valve in a hydrogen fuel cell according to claim 4, characterized in that, First PWM drive frequency f L The lowest value within the recommended operating frequency range for proportional valves.

6. The method for controlling a proportional solenoid valve in a hydrogen fuel cell according to claim 4, characterized in that, Second PWM drive frequency f H The frequency is above several kilohertz.

7. The method for controlling a proportional solenoid valve in a hydrogen fuel cell according to claim 4, characterized in that, When the sensor is a displacement sensor, the amplitude attenuation coefficient k It is 0.

2.

8. The method for controlling a proportional solenoid valve in a hydrogen fuel cell according to claim 1, characterized in that, The resonant waveform is a waveform whose periodic integral sum is 0.

9. The method for controlling a proportional solenoid valve in a hydrogen fuel cell according to claim 1, characterized in that, The closed-loop controller is a PID controller, a fuzzy controller, a model predictive controller, or a robust controller.

10. A method for controlling a proportional solenoid valve in a hydrogen fuel cell according to claim 1, characterized in that, After superimposing the closed-loop control output with the resonant waveform output, the obtained duty cycle setting value is subjected to amplitude limiting processing, restricting it to the range of 0% to 100%.

Images