A fast and accurate prediction method for duty ratio-frequency response characteristics of high-speed on-off valves

Abstract

The application discloses a kind of high-speed switch valve duty cycle-frequency response characteristic fast and accurate prediction method, belong to high-speed switch valve field.First, according to the selected driving mode, periodically open-close test is carried out to the high-speed switch valve to be measured, the motion state of high-speed switch valve spool and the starting and ending time of each motion state are recorded, the opening lag time, opening motion time, closing lag time and closing motion time of high-speed switch valve are obtained;Then calculate duty cycle boundary value;The relationship between the highest working frequency of high-speed switch valve and duty cycle when greater than duty cycle boundary value and the relationship between the highest working frequency of high-speed switch valve and duty cycle when less than duty cycle boundary value are established respectively, the two relationship formulas are combined to generate duty cycle-frequency response characteristic curve.The application can realize the fast generation of duty cycle-frequency response curve through once dynamic characteristic and current characteristic measurement.

Description

Technical Field

[0001] This invention belongs to the field of high-speed switching valves, and more specifically, relates to a rapid and accurate prediction method for the duty cycle-frequency response characteristics of high-speed switching valves. Background Technology

[0002] As a core component of digital hydraulic technology, high-speed switching valves achieve high-precision control of flow and pressure through high-frequency opening and closing actions. They have advantages such as fast response speed, high reliability, and strong anti-pollution ability, and have been widely used in aerospace, engineering machinery and high-end manufacturing fields.

[0003] In hydraulic systems, the frequency response characteristics of high-speed switching valves are crucial indicators of their dynamic performance. They determine the highest operating frequency at which the valve can stably open and close under different driving conditions, directly impacting the system's control bandwidth, dynamic response, and stability. When the driving frequency exceeds the valve's limiting frequency, the valve core cannot achieve complete opening and closing, easily leading to flow fluctuations, pressure oscillations, or even system instability. Therefore, obtaining the full duty cycle-frequency response characteristic curve of a high-speed switching valve is of great significance for valve design optimization and system application.

[0004] In existing technologies, obtaining the duty cycle-frequency response curve mainly relies on the point-by-point frequency scanning method. The basic principle of this method is as follows: First, the duty cycle of the drive signal is fixed. Then, the frequency of the input signal is gradually increased, maintaining a stable period after each frequency increase to ensure the high-speed switching valve responds fully under these conditions. Subsequently, by measuring signals such as valve flow rate changes, valve core displacement curves, or outlet pressure fluctuations, it is determined whether the valve core can achieve complete opening and closing. If the valve core can still stably complete fully open and fully closed actions at this frequency, then this frequency is considered acceptable; when the frequency continues to increase to the point where the valve core cannot fully open and close, this frequency is determined as the highest operating frequency at that duty cycle. By repeating the above process at different duty cycles, the duty cycle-frequency response curve is plotted point by point.

[0005] However, while intuitive, this method has significant limitations. First, it is inefficient, requiring multiple frequency boosts and lengthy observations for each duty cycle, often taking several hours. Second, it relies on specialized hydraulic test benches and high-precision sensors, resulting in demanding and costly experimental conditions. Third, the test results are susceptible to factors such as oil temperature, contamination, installation errors, and operator experience, leading to insufficient repeatability and consistency. Therefore, existing point-by-point scanning methods are insufficient for practical needs, especially in the design phase and field applications. There is an urgent need for a method that can rapidly and quantitatively predict the complete duty cycle-frequency response curve under limited experimental conditions to improve testing efficiency, reduce costs, and enhance the reliability and versatility of the results. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a rapid and accurate prediction method for the duty cycle-frequency response characteristics of high-speed switching valves. This method theoretically analyzes the relationship between the duty cycle-frequency response characteristics of high-speed switching valves and their opening and closing times. Then, it experimentally obtains the valve core opening and closing time parameters either directly using a laser displacement sensor or indirectly through the coil current characteristics. These key time parameters are then used as inputs into the prediction formula to quickly calculate the complete duty cycle-frequency response curve.

[0007] To achieve the above objectives, the present invention provides a rapid and accurate method for predicting the duty cycle-frequency response characteristics of a high-speed switching valve, comprising the following steps:

[0008] 1) Under the selected drive mode, perform an opening and closing test on the high-speed switching valve under test to obtain the opening lag time, opening motion time, closing lag time and closing motion time of the high-speed switching valve.

[0009] 2) Based on the times obtained in step 1), obtain the duty cycle boundary value of the high-speed switching valve under test in the selected drive mode;

[0010] 3) In the range where the duty cycle is less than the duty cycle threshold, establish the relationship between the maximum operating frequency of the high-speed switching valve and the duty cycle based on the opening lag time and opening motion time; in the range where the duty cycle is greater than the duty cycle threshold, establish the relationship between the maximum operating frequency of the high-speed switching valve and the duty cycle based on the closing lag time and closing motion time.

[0011] 4) Combine the relationship between the highest operating frequency and the duty cycle of the high-speed switching valve under different duty cycles to obtain the duty cycle-frequency response characteristic curve of the high-speed switching valve under a given driving mode. The duty cycle-frequency response characteristic curve is the relationship curve between the duty cycle and the highest operating frequency under that duty cycle.

[0012] According to a preferred embodiment of the present invention, the driving mode in step 1) is single-voltage driving, three-voltage driving or preloaded multi-voltage driving; the preloaded multi-voltage driving has an additional preloaded voltage stage before the start-up stage of the three-voltage driving. The preloaded voltage stage applies a preloaded voltage to the high-speed switching valve so that the coil current is maintained at a stable value less than the start-up current.

[0013] According to a preferred embodiment of the present invention, the valve core begins to open when it transitions from a stationary state to an opening motion; the valve core fully opens when it is fully open; the valve core begins to close when it transitions from a fully open state to a closing motion; and the valve core fully closes when it is fully closed. The valve core's start-opening, full-opening, start-closing, and full-closing times are obtained by a valve core displacement sensor detecting the valve core's motion state and the corresponding times for each motion state, or by detecting the current curve of a high-speed switching valve and obtaining it based on the characteristics of the current curve.

[0014] This invention also provides a fast and accurate prediction system for the duty cycle-frequency response characteristics of a high-speed switching valve, comprising:

[0015] The opening and closing test system is used to perform periodic opening and closing tests on the high-speed switching valve under test according to the selected drive mode, record the movement state of the valve core of the high-speed switching valve and the start and end times of each movement state, and obtain the opening lag time, opening movement time, closing lag time and closing movement time of the high-speed switching valve.

[0016] The duty cycle boundary value calculation unit is used to calculate the duty cycle boundary value based on the opening lag time, opening motion time, closing lag time and closing motion time obtained from the opening and closing test system.

[0017] The duty cycle-frequency response curve generation module is used to establish, based on the opening lag time, opening motion time, closing lag time, and closing motion time obtained from the opening and closing test system, the relationship between the highest operating frequency and duty cycle of the high-speed switching valve when it is greater than the duty cycle threshold and the relationship between the highest operating frequency and duty cycle of the high-speed switching valve when it is less than the duty cycle threshold. The two relationships are then combined to generate the duty cycle-frequency response curve.

[0018] Compared with the prior art, the present invention has the following effects and advantages:

[0019] 1) This invention combines the dynamic characteristic parameters of a high-speed switching valve, such as the opening and closing lag time and the opening and closing motion time, with the current response characteristics to directly predict the duty cycle-frequency response curve. The key time parameters among the dynamic characteristic parameters can be obtained directly from the valve core displacement, or indirectly from the current characteristics (such as inflection points) when displacement cannot be measured. This method extracts the key time parameters through a single measurement of both dynamic and current characteristics, and then derives the maximum operating frequency under different duty cycles, achieving rapid generation of the duty cycle-frequency response curve—an advantage not possessed by traditional frequency response testing methods.

[0020] 2) This invention distinguishes frequency constraints in different duty cycle ranges, using different constraints for quantitative prediction in small and large duty cycles, unlike simple prediction using overall time, thus improving model accuracy. Under small duty cycle conditions, the highest frequency is mainly limited by the valve core opening time; under large duty cycle conditions, the highest frequency is mainly constrained by the closing time.

[0021] 3) This invention proposes a mathematical relationship between duty cycle and maximum operating frequency, forming a mathematical frequency response prediction curve, which significantly improves computational efficiency and repeatability. Attached Figure Description

[0022] Figure 1 This is a schematic diagram showing the voltage signal, coil current, and valve core displacement of a high-speed switching valve under three-voltage drive for one cycle.

[0023] Figure 2 This is a schematic diagram of a system structure for indirectly detecting valve core displacement through current characteristics.

[0024] Figure 3 This is a comparison chart of the predicted and actual results of the duty cycle-frequency response curve under three-voltage drive. Detailed Implementation

[0025] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0026] The duty cycle-frequency response characteristics of high-speed switching valves are closely related to their dynamic characteristics, and while they differ under different driving methods, they also share commonalities. The duty cycle-frequency response characteristics under different driving methods all have a duty cycle cutoff value (the maximum operating frequency corresponds to this cutoff value). In the range below this cutoff value, the maximum operating frequency increases with increasing duty cycle; in the range above this cutoff value, the maximum operating frequency decreases with increasing duty cycle. Therefore, the same approach can be used to establish the duty cycle-frequency response characteristics under different driving methods.

[0027] In existing methods in this field, the duty cycle-frequency response curve is typically plotted based on whether the valve core can be fully opened and closed. This curve represents the highest operating frequency at which the high-speed switching valve can respond (fully open and close within one cycle) under different fixed duty cycles. When the operating frequency of the high-speed switching valve at a certain fixed duty cycle is higher than the corresponding highest operating frequency in its duty cycle-frequency response characteristic, the high-speed switching valve cannot achieve full opening or full closing of the valve core within one opening and closing cycle. In this case, the high-speed switching valve cannot function properly.

[0028] A high-speed switching valve's opening and closing cycle consists of an opening phase and a closing phase, with the opening and closing cycle time being... , , These are the total opening time and total closing time of the high-speed switching valve, and the opening / closing cycle frequency. Duty cycle of one start-stop cycle .

[0029] The driving modes commonly used in this field for high-speed switching valves are mainly single-voltage drive, three-voltage drive, or preloaded multi-voltage drive.

[0030] In this single-voltage drive, a single opening and closing cycle of the high-speed switching valve is divided into only two phases: opening and closing. A fixed high voltage (e.g., 24V) is applied during the opening phase, and zero voltage is applied during the closing phase. The high-speed switching valve opens under high voltage and closes when zero voltage is applied.

[0031] like Figure 1 As shown, three-voltage drive is a more refined drive mode, which divides one opening and closing cycle of a high-speed switching valve into an opening phase ①, an opening sustaining phase ②, a closing phase ③, and a closing sustaining phase ④. During the opening phase, a fixed high voltage (e.g., 24V) is applied. During the opening sustaining phase, a sustaining voltage is applied (the sustaining voltage is a high-frequency square wave voltage signal; under its loading, the coil current in the high-speed switching valve remains at the closing current). The above 5%-10% stable value During the open-up maintenance phase, the valve core of the high-speed switching valve remains fully open. During the close-up phase, a reverse high voltage (e.g., -24V) is applied to achieve rapid closing. During the close-up maintenance phase, zero voltage is applied to maintain low power consumption.

[0032] The preloaded multi-voltage drive adds a preloaded voltage stage before the opening stage of the three-voltage drive. The preloaded voltage stage applies a preloaded voltage through the high-speed switching valve (the preloaded voltage is a high-frequency square wave voltage signal. Under its loading, the coil current in the high-speed switching valve remains at a stable value that is 5%-10% smaller than the opening current; under its action, the valve core of the high-speed switching valve remains closed, but because the coil current is close to the opening current, it can open quickly in the opening stage).

[0033] The movement of the valve core is not synchronized with the application of the driving voltage; the valve core's movement response often lags behind the adjustment of the driving voltage. For example... Figure 1 As shown, the total startup time can be further divided into startup lag time. Start your exercise time Turn-on current sustaining time and turn-on current adjustment time Among them, the start-up lag time The time from the initial moment of the opening phase to the moment the valve core begins to open (this time characterizes the delay in the valve core's movement from being subjected to a high voltage U); opening movement time The time from the start of valve core opening to full opening (during which the valve core is constantly in motion, a key parameter characterizing valve opening performance); opening current sustaining time. The start-up sustaining current I in the three-voltage stage and the pre-loaded multi-voltage stage. hold Application duration, start-up current adjustment time In the three-voltage stage and the preloaded multi-voltage stage, the coil current is determined by I... max Adjust to I hold The duration of the shutdown; correspondingly, the total shutdown time can also be further divided into shutdown lag time. Turn off exercise time , current holding time and the time to adjust the current to the off The closing hysteresis time is the time from the initial moment of the closing phase to the moment when the valve core begins to close (this time characterizes the delay from the valve core being loaded with a reverse high voltage -U (or zero voltage under single voltage drive) to the valve core opening and closing movement); the closing movement time is the time from the valve core starting to close to being fully closed (during this time, the valve core is always in motion and is a key parameter characterizing the valve closing performance).

[0034] Figure 1 middle, This is the critical opening current of the valve core. At this point, the electromagnetic force just overcomes the resistance of the spring compression force and friction, putting the valve core in a critical opening state. This is the critical closing current of the valve core. At this point, the spring return force exactly counteracts the resistance of electromagnetic force and friction, causing the valve core to be in a critical closing state.

[0035] Therefore, by simply performing an opening and closing test on the high-speed switching valve under the selected drive mode, recording the movement state of the valve core and the start and end times of each movement state, the valve core's start opening time, full opening time, start closing time, and full closing time can be obtained. The opening lag time, opening motion time, closing lag time, and closing motion time of the high-speed switching valve can then be calculated. Here, the opening lag time is the difference between the valve core's start opening time and the initial time of the opening phase; the opening motion time is the difference between the full opening time and the valve core's start opening time; the closing lag time is the difference between the valve core's start closing time and the initial time of the closing phase; and the closing motion time is the difference between the full closing time and the valve core's start closing time. Specifically, the valve core's start opening time is the moment when the valve core transitions from a stationary state to an opening motion; the full opening time is the moment when the valve core is fully open; the start closing time is the moment when the valve core transitions from a fully open state to a closing motion; and the full closing time is the moment when the valve core is fully closed.

[0036] The valve core's motion state and the corresponding time of each motion state can be obtained in various ways. For high-speed switching valves equipped with valve core displacement sensors or those that can be equipped with valve core displacement sensors, the valve core's motion state and the corresponding time of each motion state can be directly obtained through the valve core displacement sensor. For high-speed switching valves that cannot be equipped with valve core displacement sensors, the valve core displacement can be indirectly detected through current characteristics.

[0037] like Figure 2 The diagram illustrates a system for indirectly detecting valve spool displacement using current characteristics. The system includes a voltage source 1, a computer 2, a current acquisition card 3, a high-speed switching valve driver 4, and a high-speed switching valve 5. The high-speed switching valve driver 4 is configured with the pulse width modulation (PWM) signal period and duty cycle (0-100%) for driving the high-speed switching valve 5, as well as the driving mode (e.g., single-voltage drive, three-voltage drive, multi-voltage drive). When the valve spool of the high-speed switching valve 5 moves, its coil current characteristics and valve spool displacement have corresponding characteristic points. The current acquisition card 3 is used to acquire the coil current of the high-speed switching valve to indirectly detect the valve spool displacement. Specific detection methods are detailed in existing technologies, such as CN202410266937, which discloses a solenoid valve dynamic performance detection system and method based on current characteristics. This system can accurately and reliably detect the valve spool movement process, precisely identify the dynamic characteristics of the solenoid valve, and obtain the movement state of the high-speed switching valve spool and the start and end times of each movement state.

[0038] Considering the high-speed switching valve under different duty cycles of opening and closing, the maximum operating frequency is limited. The dominant factors are different: when the duty cycle When it is relatively small, that is, the total on time For shorter periods, the opening time ( The influence of duty cycle is dominant. When the value is large, turn off dynamic time ( The influence of ) is dominant. With increasing work frequency Approaching the limit The dynamic characteristics will change significantly due to the coupling of the coil current characteristics; and the pattern of this change varies with the driving method, resulting in differences in the shape of the duty cycle-frequency response curve.

[0039] Based on this, the present invention uses the duty cycle boundary value as the boundary, when When using the small duty cycle calculation formula, when When using a large duty cycle calculation formula, the duty cycle is employed. Specifically, when the duty cycle... When the duty cycle is 0, there is no driving voltage, and the valve core cannot open. With a constant driving voltage (100%), the valve core cannot close. (Duty cycle...) It is possible to achieve complete opening and closing of the valve core of a high-speed switching valve in any of these situations.

[0040] Specifically, the fast and accurate prediction method for the duty cycle-frequency response characteristics of high-speed switching valves of the present invention includes the following steps:

[0041] 1) Under the selected drive mode (single voltage drive, three voltage drive or preloaded multi-voltage drive), perform the opening and closing test on the high-speed switching valve under test to obtain the opening lag time, opening motion time, closing lag time and closing motion time of the high-speed switching valve.

[0042] 2) Based on the times obtained in step 1), obtain the duty cycle boundary value of the high-speed switching valve under test in the selected drive mode. ;

[0043] The duty cycle threshold is related to the drive mode, where:

[0044] In single-voltage drive mode, the duty cycle cutoff value is:

[0045] ;

[0046] In the three-voltage drive mode, the duty cycle cutoff value is:

[0047] ;

[0048] In multi-voltage drive mode, the duty cycle cutoff value is:

[0049] ;

[0050] in, , These are the on lag time and the off lag time, respectively. , These refer to the start and end times of exercise.

[0051] 3) In the range where the duty cycle is less than the duty cycle threshold, establish the relationship between the maximum operating frequency of the high-speed switching valve and the duty cycle based on the opening lag time and opening motion time; in the range where the duty cycle is greater than the duty cycle threshold, establish the relationship between the maximum operating frequency of the high-speed switching valve and the duty cycle based on the closing lag time and closing motion time.

[0052] a. In the interval where the duty cycle is less than the duty cycle threshold.

[0053] In single-voltage drive mode, the maximum operating frequency is directly proportional to the duty cycle, and the proportionality coefficient is the reciprocal of the sum of the start-up lag time and the start-up motion time:

[0054] ;

[0055] In both three-voltage drive mode and multi-voltage drive mode, the maximum operating frequency is directly proportional to the duty cycle. The proportionality coefficient is the reciprocal of the sum of the turn-on lag time and the turn-on motion time minus the turn-off lag time.

[0056] .

[0057] b. In the interval where the duty cycle is greater than the duty cycle threshold, let the duty cycle be denoted as . The highest operating frequency in single-voltage drive mode and three-voltage drive mode is Proportional: Its proportionality coefficient is the reciprocal of the sum of the closing lag time and the closing motion time.

[0058] ;

[0059] Maximum operating frequency in multi-voltage drive mode and The proportionality coefficient is the reciprocal of the sum of the closing lag time and the closing motion time minus the opening lag time.

[0060] .

[0061] 4) Combine the relationship between the highest operating frequency and the duty cycle of the high-speed switching valve under different duty cycles to obtain the duty cycle-frequency response characteristic curve of the high-speed switching valve under a given driving mode. The duty cycle-frequency response characteristic curve is the relationship curve between the duty cycle and the highest operating frequency under that duty cycle.

[0062] This invention also provides a fast and accurate prediction system for the duty cycle-frequency response characteristics of a high-speed switching valve, comprising:

[0063] The opening and closing test system is used to perform periodic opening and closing tests on the high-speed switching valve under test according to the selected drive mode, record the movement state of the valve core of the high-speed switching valve and the start and end times of each movement state, and obtain the opening lag time, opening movement time, closing lag time and closing movement time of the high-speed switching valve.

[0064] The duty cycle boundary value calculation unit is used to calculate the duty cycle boundary value based on the opening lag time, opening motion time, closing lag time and closing motion time obtained from the opening and closing test system.

[0065] The duty cycle-frequency response curve generation module is used to establish, based on the opening lag time, opening motion time, closing lag time, and closing motion time obtained from the opening and closing test system, the relationship between the highest operating frequency and duty cycle of the high-speed switching valve when it is greater than the duty cycle threshold and the relationship between the highest operating frequency and duty cycle of the high-speed switching valve when it is less than the duty cycle threshold. The two relationships are then combined to generate the duty cycle-frequency response curve.

[0066] The present invention will be further described below with reference to specific embodiments.

[0067] Single-voltage drive consists of only two stages: high voltage and zero voltage. As the operating frequency increases (cycle time shortens), the total on-time... Total closing time Simultaneously reduce proportionally. The current holding time should be reduced first. / In this way, the dynamic and current characteristics of the high-speed switching valve will not change. When the cycle time is insufficient to guarantee the current sustaining time... / In the presence of current adjustment time / This will decrease the current, preventing the coil current from reaching a steady state, thus altering the dynamic characteristics of the high-speed switching valve. When the cycle time is insufficient to guarantee the current adjustment time... / That is, current adjustment time / When the voltage is reduced to zero, the opening and closing process of the high-speed switching valve will be completed by both high-voltage and zero-voltage stages, thus bringing the valve core to a critical state. At this time, the high-speed switching valve operates at its highest frequency. The critical state below, corresponding to the total on time Recorded as the minimum necessary start time Closing time Recorded as the minimum necessary closing time The approximate highest operating frequency under a small duty cycle was obtained. Approximate highest operating frequency under large duty cycle When the operating frequency continues to increase, the high-speed switching valve can no longer achieve a complete opening and closing process. When the opening and closing times reach their minimum simultaneously, the high-speed switching valve will operate at its limiting frequency. Its corresponding duty cycle is At this point, the high-speed switching valve operates under extreme conditions, where it is fully opened and then immediately closed, and fully closed and then immediately opened again.

[0068] Under single-voltage drive, for a certain high-speed switching valve under test, the experimental results were obtained. , , , The approximate highest operating frequency under a small duty cycle Approximate highest operating frequency under large duty cycle Approximate threshold frequency The corresponding duty cycle (duty cycle threshold) is The final duty cycle-frequency response prediction data are shown in Table 1.

[0069] Table 1. Duty cycle-frequency response prediction data for high-speed switching valves under single-voltage drive.

[0070]

[0071] The three-voltage drive includes a high-voltage turn-on phase ①, a low-voltage sustaining phase ②, a reverse high-voltage turn-off phase ③, and a zero-voltage phase ④. The duration of these phases is... Figure 1 The middle is represented as arrive The low-voltage sustaining phase ② maintains the coil current at the off-current level. A stable value of 5%-10% above. This reduces the shutdown hysteresis time. During the reverse high-voltage phase ③, the current is rapidly reduced, similarly reducing the shutdown hysteresis time. Figure 1 As shown.

[0072] Under three-voltage drive, for a certain high-speed switching valve under test, the experimental results were obtained. , , , The approximate highest operating frequency under a small duty cycle Approximate highest operating frequency under large duty cycle Approximate threshold frequency The corresponding duty cycle (duty cycle threshold) is The final duty cycle-frequency response prediction data are shown in Table 2.

[0073] Table 2. Duty cycle-frequency response prediction data for high-speed switching valves under three-voltage drive.

[0074]

[0075] The preloaded multi-voltage drive includes stages of preload, high-voltage turn-on, low-voltage sustain, reverse high-voltage turn-off, and zero-voltage. The preload stage ensures that the coil current reaches the turn-on current before the valve core turn-on command signal arrives. A value between 5% and 10% below This reduces the turn-on hysteresis time, and the low-voltage maintenance and reverse high-voltage shutdown functions are similar to those in three-voltage drive.

[0076] Under preloaded multi-voltage drive, for a certain high-speed switching valve under test, the experimental results were as follows: , , , The approximate highest operating frequency under a small duty cycle Approximate highest operating frequency under large duty cycle Approximate threshold frequency The corresponding duty cycle (duty cycle threshold) is The final duty cycle-frequency response prediction data are shown in Table 3.

[0077] Table 3. Duty cycle-frequency response prediction data for high-speed switching valves under multi-voltage drive.

[0078]

[0079] Finally, the duty cycle-frequency response prediction data of the high-speed switching valves in Tables 1–3 were plotted into curves. The results intuitively show the frequency response trend of the high-speed switching valves under different driving methods, which can serve as an important reference in the design and application stages and provide support for the selection of driving strategies and valve performance evaluation.

[0080] The following uses a three-voltage drive as an example to verify the method of the present invention.

[0081] The duty cycle-frequency response prediction data of the high-speed switching valve under three-voltage drive obtained by the method of the present invention are shown in Table 2. The duty cycle corresponding to the approximate limiting frequency is the duty cycle boundary value. .

[0082] Experimental tests were conducted under three-voltage drive. In the duty cycle-frequency response test, changes in the duty cycle and its frequency response may cause changes in these parameter values. The experiment corrected the highest operating frequency under a small duty cycle. Compared with the prediction formula use Replacement, this is the total on-time measured in the experiment. The maximum value that can be reduced is required; otherwise, the valve core cannot fully open and close. Experimental correction is needed for the highest operating frequency under a large duty cycle. Compared with the prediction formula This is a newly added value because the total shutdown time was observed in the experiment. Without this value, malfunctions sometimes occur during continuous opening and closing of the valve core. Experiments were conducted to correct the limiting frequency. The corresponding duty cycle is ,in It is the start lag time (The initial current increases at the moment of startup, and the time decreases.) Total opening time Subtract startup lag time The value of is determined by the threshold frequency. It is the closing lag time (The lack of a maintenance phase increases the initial current and duration of shutdown.) The duty cycle-frequency response experimental data is obtained by considering the shutdown time. Table 4 shows the comparison curves between the predicted and experimental data. Figure 3 As shown.

[0083] Table 4 Experimental data on duty cycle and frequency response of high-speed switching valve under three-voltage drive.

[0084]

[0085] from Figure 3 As can be seen from the data in the table, the duty cycle-frequency response curve predicted by the method of this invention is very close to the curve obtained by fitting the experimental data, indicating that the method of this invention has high prediction accuracy. In the experiment, to obtain this curve, a large number of frequency tests were required at each duty cycle until the highest operating frequency at that duty cycle was obtained. Each data point required a significant amount of time to acquire, and the switching valve may experience fatigue during long-term experiments, so the data obtained in the later stages of the experiment may not be accurate. In contrast, the method of this invention can greatly save time, quickly generate the duty cycle-frequency response curve, and has high accuracy.

[0086] The various embodiments of the present invention 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 rapid and accurate prediction method for the duty cycle-frequency response characteristics of a high-speed switching valve, characterized in that, Includes the following steps: 1) Under the selected drive mode, perform an opening and closing test on the high-speed switching valve under test to obtain the opening lag time, opening motion time, closing lag time and closing motion time of the high-speed switching valve. 2) Based on the times obtained in step 1), obtain the duty cycle boundary value of the high-speed switching valve under test in the selected drive mode; 3) In the range where the duty cycle is less than the duty cycle threshold, establish the relationship between the maximum operating frequency of the high-speed switching valve and the duty cycle based on the opening lag time and opening motion time; in the range where the duty cycle is greater than the duty cycle threshold, establish the relationship between the maximum operating frequency of the high-speed switching valve and the duty cycle based on the closing lag time and closing motion time. 4) Combine the relationship between the highest operating frequency and the duty cycle of the high-speed switching valve under different duty cycles to obtain the duty cycle-frequency response characteristic curve of the high-speed switching valve under a given driving mode. The duty cycle-frequency response characteristic curve is the relationship curve between the duty cycle and the highest operating frequency under that duty cycle.

2. The method according to claim 1, characterized in that, In step 1), the driving mode is single-voltage drive, three-voltage drive, or pre-loaded multi-voltage drive; The single-voltage drive divides one opening and closing cycle of the high-speed switching valve into an opening phase and a closing phase. A fixed high voltage is applied during the opening phase, and zero voltage is applied during the closing phase. The three-voltage drive divides one opening and closing cycle of the high-speed switching valve into an opening phase, an opening sustaining phase, a closing phase, and a closing sustaining phase. A fixed high voltage is applied during the opening phase, a sustaining voltage is applied during the opening sustaining phase, a reverse high voltage is applied during the closing phase, and zero voltage is applied during the closing sustaining phase. The preloaded multi-voltage drive adds a preloaded voltage stage before the start-up stage of the three-voltage drive. The preloaded voltage stage applies a preloaded voltage to the high-speed switching valve to keep the coil current at a stable value that is less than the start-up current.

3. The method according to claim 2, characterized in that, During the on-up sustaining phase of the three-voltage drive, the sustaining voltage applied to the high-speed switching valve is a high voltage with a set duty cycle. Under the action of the sustaining voltage, the coil current in the high-speed switching valve remains at the off-up current. The above 5%-10% stable value During the opening and holding phase, the valve core of the high-speed switching valve remains fully open.

4. The method according to claim 1, characterized in that, In step 1), the high-speed switching valve under test is subjected to an opening and closing test, including: Drive the high-speed switching valve under test according to the selected driving mode, record the movement state of the valve core, as well as the start and end times of each movement state, to obtain the valve core's start opening time, full opening time, start closing time, and full closing time.

5. The method according to claim 4, characterized in that, In step 1), the opening lag time is the difference between the moment the valve core begins to open and the initial moment of the opening phase; the opening movement time is the difference between the moment the valve core begins to open and the moment the valve core begins to open; the closing lag time is the difference between the moment the valve core begins to close and the initial moment of the closing phase; and the closing movement time is the difference between the moment the valve core begins to close and the moment the valve core begins to close. The initial time of the turn-on phase is the rising edge of the drive signal in the drive mode; the initial time of the turn-off phase is the falling edge of the drive signal.

6. The method according to claim 2, characterized in that, The valve core begins to open when it transitions from a stationary state to an opening motion; the valve core fully opens when it is fully open; the valve core begins to close when it transitions from a fully open state to a closing motion; and the valve core fully closes when it is fully closed. The valve core's start-open, full-open, start-close, and full-close times are obtained by a valve core displacement sensor detecting the valve core's motion state and the corresponding times for each motion state, or by detecting the current curve of a high-speed switching valve and obtaining it based on the characteristics of the current curve.

7. The method according to claim 1, characterized in that, Step 2) The duty cycle threshold value is related to the driving mode, where: In single-voltage drive mode, the duty cycle cutoff value is: ； In the three-voltage drive mode, the duty cycle cutoff value is: ； In multi-voltage drive mode, the duty cycle cutoff value is: ； in, , These are the on lag time and the off lag time, respectively. , These refer to the start and end times of exercise.

8. The method according to claim 1, characterized in that, In step 3), within the interval where the duty cycle is less than the duty cycle threshold, In single-voltage drive mode, the highest operating frequency is directly proportional to the duty cycle, and the proportionality coefficient is the reciprocal of the sum of the start-up lag time and the start-up motion time. The maximum operating frequency in both the three-voltage drive mode and the multi-voltage drive mode is directly proportional to the duty cycle. The proportionality coefficient is the reciprocal of the sum of the turn-on lag time and the turn-on motion time minus the turn-off lag time.

9. The method according to claim 1, characterized in that, In step 3), within the interval where the duty cycle is greater than the duty cycle threshold, the duty cycle is denoted as . The highest operating frequency in single-voltage drive mode and three-voltage drive mode is It is directly proportional, and its proportionality coefficient is the reciprocal of the sum of the closing lag time and the closing motion time; Maximum operating frequency in multi-voltage drive mode and It is directly proportional, and its proportionality coefficient is the reciprocal of the sum of the closing lag time and the closing motion time minus the opening lag time.

10. A fast and accurate prediction system for the duty cycle-frequency response characteristics of a high-speed switching valve implementing the method of claim 1, characterized in that, include: The opening and closing test system is used to perform periodic opening and closing tests on the high-speed switching valve under test according to the selected drive mode, record the movement state of the valve core of the high-speed switching valve and the start and end times of each movement state, and obtain the opening lag time, opening movement time, closing lag time and closing movement time of the high-speed switching valve. The duty cycle boundary value calculation unit is used to calculate the duty cycle boundary value based on the opening lag time, opening motion time, closing lag time and closing motion time obtained from the opening and closing test system. The duty cycle-frequency response curve generation module is used to establish, based on the opening lag time, opening motion time, closing lag time, and closing motion time obtained from the opening and closing test system, the relationship between the highest operating frequency and duty cycle of the high-speed switching valve when it is greater than the duty cycle threshold and the relationship between the highest operating frequency and duty cycle of the high-speed switching valve when it is less than the duty cycle threshold. The two relationships are then combined to generate the duty cycle-frequency response curve.

Images