A method for automatically identifying three-voltage opening stage control parameters of a spring type electromagnetic valve

Abstract

The application discloses a method for automatically identifying control parameters of a three-voltage opening stage of a spring type electromagnetic valve, and comprises the following steps: opening the electromagnetic valve by using a reduced voltage, and recording a current curve during the process; wherein the reduced voltage is a test voltage obtained by proportionally reducing a full voltage in the three-voltage opening stage through a PWM wave; analyzing and calculating the current curve to obtain inflection point coordinates of a first inflection point; and deducing electromagnetic valve characteristic parameters under the full voltage by using the inflection point coordinates of the first inflection point, including an opening maintaining time under the full voltage and a maintaining current under the full voltage. The application automatically measures the opening maintaining time under the full voltage and the maintaining current under the full voltage in the control parameters of the three-voltage control strategy of the electromagnetic valve, realizes high response and low power consumption of the opening maintaining electromagnetic valve, and saves manpower, material resources and time.

Description

Technical Field

[0001] This invention relates to the field of solenoid valve control parameter identification, and in particular to a method for automatically identifying control parameters of a spring-type solenoid valve during the three-voltage opening stage. Background Technology

[0002] In existing technologies, spring-loaded solenoid valve control methods mainly employ a three-voltage control strategy, which includes a shut-off state (0 voltage), a forward full-voltage opening state, a holding state (holding voltage), and a reverse full-voltage shut-off state. The forward full-voltage opening state aims to enable faster valve opening, while the holding state aims to maintain the valve open with the lowest possible power consumption. If the forward full-voltage duration is too long, it can cause problems such as solenoid valve overheating and increased power consumption. Conversely, if the forward full-voltage duration is too short, it can lead to longer valve opening times. Therefore, in a three-voltage control strategy, the appropriateness of the forward full-voltage duration setting directly affects the valve opening time and power consumption.

[0003] Currently, most users of spring-loaded solenoid valves rely on reading the valve's specifications and conducting actual tests using oscilloscopes and sensors to determine the full-voltage opening time and holding current. This method is not only time-consuming, labor-intensive, and resource-intensive, but also susceptible to subjective human factors. Furthermore, because different valves have different characteristic parameters, the same controller cannot be adapted to control parameters for different valves, requiring remeasurement. Even for valves of the same model, their characteristic parameters may differ, leading to significant discrepancies in the actual control effect of the same controller. Additionally, some solenoid valves are relatively small, and when operating at full voltage, the energy surge is too rapid, making it difficult for oscilloscopes to calculate specific control parameters (such as current magnitude and opening time). Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for automatically identifying the control parameters of the three-voltage opening stage of a spring-type solenoid valve.

[0005] The objective of this invention is achieved through the following technical solution: A first aspect of the present invention provides a method for automatically identifying control parameters of a spring-loaded solenoid valve during the three-voltage opening stage, comprising the following steps: The solenoid valve is opened by reducing the voltage, and the current curve is recorded during this period; wherein, the reduced voltage is the test voltage obtained by proportionally reducing the full voltage in the three-voltage opening stage by the PWM wave. The coordinates of the first inflection point are obtained by analyzing and calculating the current curve. The inflection point coordinates of the first inflection point are used to deduce the solenoid valve characteristic parameters under full voltage, including the opening holding time and holding current under full voltage.

[0006] Furthermore, the voltage drop is 50% lower than the full voltage.

[0007] Furthermore, the recording of the current curve during this period includes: During the entire recording period, an interrupt occurs once every first preset time interval. According to the ADC sampling configuration, n current samples will be taken during this period. Every first preset time interval, the current I is linearly fitted to time t. The model used is as follows: ; in: ; ; In the formula, the value of i ranges from 1 to n; Points at the same location are obtained within each first preset time period and used as fitting points within the corresponding first preset time period. The current curve is plotted using the fitting points obtained at each first preset time interval throughout the entire recording period.

[0008] Furthermore, the recording period is 500ms, the first preset time is 100us; the value of n is 21, and the point with the same position is the 10th point.

[0009] Furthermore, the coordinates of the first inflection point are the coordinates of the fitting point when the slope of the current curve first becomes negative.

[0010] Furthermore, the process of deriving the solenoid valve characteristic parameters under full voltage using the inflection point coordinates of the first inflection point includes the opening holding time and holding current under full voltage, comprising: The time corresponding to the first inflection point is used as the on-up sustain time under the test voltage. t 1 The corresponding current I 1 At the same time, let The current at that time point is obtained through the current curve. I 2 Set the full voltage to U S0 The test voltage is U S1 This reduces the voltage by a certain percentage. The on-time under full voltage is t 0 ; Based on the empirical formula for the suction force of a solenoid valve, the force required to open the solenoid valve is constant, meaning the required current is constant. Therefore, the opening holding time under full voltage is... t 0The corresponding holding current under full voltage is also... I 1 ; The on-time under full voltage is t 0 The calculation formula is as follows: ;

[0011] Among them, the first parameter The second parameter .

[0012] The beneficial effects of this invention are: This invention uses a voltage reduction method to collect the current curve under reduced voltage, and uses the inflection point coordinates of the first inflection point in the current curve to automatically measure the opening and holding time and holding current under full voltage in the control parameters of the three-voltage control strategy of the solenoid valve, thereby realizing a high-response, low-power opening and holding solenoid valve, saving manpower, material resources and time. Attached Figure Description

[0013] Figure 1 A flowchart of a method for automatically identifying control parameters of a spring-loaded solenoid valve during the three-voltage opening stage, provided as an exemplary embodiment of the present invention; Figure 2 A schematic diagram of a current curve provided for an exemplary embodiment of the present invention; Figure 3 An equivalent circuit diagram of a solenoid valve provided for an exemplary embodiment of the present invention; Figure 4 A simplified equivalent circuit diagram of a solenoid valve provided for an exemplary embodiment of the present invention. Detailed Implementation

[0014] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] In the description of this invention, it should be noted that the directions or positional relationships indicated by terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0016] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0017] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0018] See Figure 1 , Figure 1 The flowchart illustrates an exemplary embodiment of the present invention providing a method for automatically identifying control parameters of a spring-loaded solenoid valve during the three-voltage opening phase, comprising the following steps: The solenoid valve is opened by reducing the voltage, and the current curve is recorded during this period; wherein, the reduced voltage is the test voltage obtained by proportionally reducing the full voltage in the three-voltage opening stage by the PWM wave. The coordinates of the first inflection point are obtained by analyzing and calculating the current curve. The inflection point coordinates of the first inflection point are used to deduce the solenoid valve characteristic parameters under full voltage, including the opening holding time and holding current under full voltage.

[0019] Specifically, in the prior art, some solenoid valves are relatively small, and when using full voltage, the energy surges too quickly, making it difficult for the oscilloscope to calculate the specific control parameters. Therefore, in this exemplary embodiment, the current curve under reduced voltage is acquired by using a voltage reduction method, and the coordinates of the first inflection point in the current curve are used to automatically measure the opening and holding time under full voltage and the holding current under full voltage in the control parameters of the three-voltage control strategy of the solenoid valve. This achieves a high-response, low-power opening and holding solenoid valve, saving manpower, material resources and time.

[0020] The following will explain the specific implementation method of each step: More preferably, in an exemplary embodiment, the voltage drop is 50% relative to the full voltage.

[0021] Specifically, in this exemplary embodiment, when the equivalent voltage of the full voltage is 12V, the voltage drop can be 6V.

[0022] More preferably, in an exemplary embodiment, recording the current curve during this period includes: During the entire recording period, an interrupt occurs once every first preset time interval. According to the ADC sampling configuration, n current samples will be taken during this period. Every first preset time interval, the current I is linearly fitted to time t. The model used is as follows: ;

[0023] in: ; ;

[0024] In the formula, the value of i ranges from 1 to n; Points at the same location are obtained within each first preset time period and used as fitting points within the corresponding first preset time period. The current curve is plotted using the fitting points obtained at each first preset time interval throughout the entire recording period.

[0025] Specifically, in this exemplary embodiment, the content of the preferred exemplary embodiment is described, and other optional content is deduced similarly: During the entire 500ms recording period, an interrupt occurs every 100µs. According to the ADC sampling configuration, 21 current samples are taken during each 100µs period, and the current is fitted against time. The entire recording period consists of 5000 100µs intervals. Simultaneously, to reduce data space, given the achieved accuracy, only one point of the same location is taken within each first preset time interval as the fitting point for the subsequent current curve (preferably the 10th point, i.e., the average point). The final fitted current curve is as follows: Figure 2 As shown.

[0026] exist Figure 2 In the diagram, point A represents the initial opening of the solenoid valve, point B is the first inflection point indicating the start of the valve's movement, point C is the second inflection point indicating the end of the valve's movement, and point D is the point where the current reaches its maximum value. The solenoid valve opening process is as follows: First, before point A, no current flows through the solenoid valve, and the valve core remains closed under the action of the spring force. From point A to point B, due to the inductive characteristics, the current cannot change immediately, so it gradually increases under the action of voltage, and at point B, the electromagnetic force generated by the current and the spring force are in balance. From point B to point C, the valve core begins to move. Due to the decrease in the air gap of the magnetic circuit, the air gap magnetic resistance decreases, and the coil inductance increases, causing the current to decrease. At point C, the valve core moves to its final position. From point C to point D, under the action of voltage, the current continues to be at its maximum and reaches its maximum value at point D.

[0027] More preferably, in an exemplary embodiment, the coordinates of the first inflection point are the coordinates of the fitting point when the slope of the current curve first becomes negative.

[0028] Specifically, in this exemplary embodiment, that is Figure 2 Point B in the diagram. It should be noted that when the slope of the current is... When the value first becomes negative, this point is identified as point B, the first inflection point of the current curve.

[0029] More preferably, in an exemplary embodiment, the step of using the inflection point coordinates of the first inflection point to deduce the solenoid valve characteristic parameters under full voltage, including the opening holding time and holding current under full voltage, includes: The time corresponding to the first inflection point is used as the on-up sustain time under the test voltage. t 1 The corresponding current I 1 At the same time, let The current at that time point is obtained through the current curve. I 2 Set the full voltage to U S0 The test voltage is U S1 This reduces the voltage by a certain percentage. The on-time under full voltage is t 0 ; Based on the empirical formula for the suction force of a solenoid valve, the force required to open the solenoid valve is constant, meaning the required current is constant. Therefore, the opening holding time under full voltage is... t 0 The corresponding holding current under full voltage is also... I 1 ; The on-time under full voltage is t 0 The calculation formula is as follows: ;

[0030] Among them, the first parameter The second parameter .

[0031] Specifically, in this exemplary embodiment, the specific calculation method for the turn-on sustaining time and sustaining current under full voltage is disclosed, and its derivation process is as follows: like Figure 1 As shown, the time corresponding to the first inflection point is used as the on-up sustaining time under the test voltage. t 1 The corresponding current I 1 At the same time, let The current at that time point is obtained through the current curve. I 2Set the full voltage to U S0 The test voltage is U S1 This reduces the voltage by a certain percentage. The on-time under full voltage is t 0 ; Based on the empirical formula for the suction force of a solenoid valve:

[0032] in, The permeability of free space, ; S magnetic circuit area (m²) 2 ); Kf The leakage flux coefficient; For the air gap of the solenoid valve; N Number of turns I Let be the electric current. From this formula, we can see that the magnitude of the electromagnetic force is directly proportional to the square of the current.

[0033] Based on the above principles, to achieve high-speed valve opening, the time of the ABC curve needs to be shortened. Since the force required to open the solenoid valve is constant, meaning the required current is constant, the goal is to reach the opening current (the current corresponding to point B) more quickly. Furthermore, the solenoid valve coil can be considered equivalent to an inductor; therefore, the time of this curve segment is related to the applied voltage. Thus, increasing the opening time means increasing the applied voltage. However, according to actual test results, when the voltage is too high, the current inflection point becomes indistinct or even unmeasurable. Therefore, to better identify point B, this method uses a PWM wave to control the switch at a certain ratio to lower the voltage and measure and plot the current curve.

[0034] Once the valve is open, it is sufficient to maintain a balance between the electromagnetic force and the spring force. If the current is maintained at point C, the electromagnetic force may be insufficient to maintain the valve core position due to oscillations during current control, causing repeated displacement of the valve core. Therefore, for safety, the current is maintained at point B, which is independent of the external voltage, thereby reducing power consumption during the holding phase. Thus, during the holding phase, this method employs closed-loop current control. The equivalent circuit diagram of the solenoid valve is shown below. Figure 1 As shown, the simplified equivalent circuit diagram is as follows: Figure 2 As shown.

[0035] Furthermore, based on the empirical formula for the suction force of a solenoid valve, the force required to open the solenoid valve is constant, meaning the required current is constant. Therefore, the opening holding time under full voltage is... t 0 The current should also be I 1 The corresponding formula is as follows: ; ;

[0036] In the formula, R represents the resistance in the equivalent circuit of the solenoid valve. Represents the time constant; solving the above formula yields:

[0037] Among them, the first intermediate parameter Let the second intermediate parameter Then we have:

[0038]

[0039] The two formulas above can be transformed to obtain:

[0040] At the same time because Then we have:

[0041] again ,have:

[0042] The value of the second intermediate parameter G is obtained by simplification:

[0043] Finally, the value of the first intermediate parameter M is calculated:

[0044]

[0045] The on-time under full voltage is calculated using the first intermediate parameter M. t 0 .pass I 1 , I 2 , t 1 , t 2 and proportion K The duration of the full voltage at the original voltage can then be measured. After this, the current is maintained at... I 1 This means that the solenoid valve can achieve high response and low power consumption during the opening and holding phase.

[0046] Using the above methods, the full-voltage opening time and holding current in the three-voltage control strategy parameters of the solenoid valve can be automatically measured, realizing a high-response, low-power opening and holding solenoid valve, saving manpower, material resources and time.

[0047] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for automatically identifying control parameters of a spring-loaded solenoid valve during the three-voltage opening stage, characterized in that: Includes the following steps: The solenoid valve is opened by reducing the voltage, and the current curve is recorded during this period; wherein, the reduced voltage is the test voltage obtained by proportionally reducing the full voltage in the three-voltage opening stage by the PWM wave. The inflection point coordinates of the first inflection point are obtained by analyzing and calculating the current curve. The inflection point coordinates of the first inflection point are the coordinates of the fitting point when the slope of the current curve first becomes negative. Using the inflection point coordinates of the first inflection point, the characteristic parameters of the solenoid valve under full voltage are derived, including the opening holding time and holding current under full voltage, specifically including: The time corresponding to the first inflection point is used as the on-up sustaining time t1 under the test voltage, and the corresponding current I1 is also set; at the same time, let The current I2 at that time point is obtained through the current curve; the total voltage is set to U. S0 The test voltage is U S1 This reduces the voltage by a certain percentage. The on-time under full voltage is t0; According to the empirical formula for the suction force of a solenoid valve, the force required to open the solenoid valve is constant, which means that the required current is constant. Therefore, the opening holding time under full voltage is t0, and the corresponding holding current under full voltage is I1. The formula for calculating the on-up sustaining time t0 under full voltage is as follows: ； Among them, the first parameter The second parameter .

2. The method for automatically identifying control parameters of the three-voltage opening stage of a spring-type solenoid valve according to claim 1, characterized in that: The voltage reduction is 50% compared to the full voltage.

3. The method for automatically identifying control parameters of the three-voltage opening stage of a spring-type solenoid valve according to claim 1, characterized in that: The recording of the current curve during this period includes: During the entire recording period, an interrupt occurs once every first preset time interval. According to the ADC sampling configuration, n current samples will be taken during this period. Every first preset time interval, the current I is linearly fitted to time t. The model used is as follows: ； in: ； ； In the formula, the value of i ranges from 1 to n; Points at the same location are acquired within each first preset time period and used as fitting points within the corresponding first preset time period. The current curve is plotted using the fitting points obtained at each first preset time interval throughout the entire recording period.

4. The method for automatically identifying control parameters of the three-voltage opening stage of a spring-type solenoid valve according to claim 3, characterized in that: The recording period is 500ms, the first preset time is 100us; the value of n is 21, and the point with the same position is the 10th point.

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