CN-122018575-A - Water flow control method and system for pulse electromagnetic valve

CN122018575ACN 122018575 ACN122018575 ACN 122018575ACN-122018575-A

Abstract

The invention relates to the technical field of water flow control, in particular to a water flow control method and system for a pulse electromagnetic valve, wherein the method comprises the steps of acquiring upstream water pressure, downstream water pressure, actual flow and target flow of the pulse electromagnetic valve, and preprocessing acquired original data to obtain pressure difference and control requirements; the method comprises the steps of inputting differential pressure and control requirements into a fuzzy controller, generating a pulse duty ratio reference value through fuzzy processing, fuzzy rule reasoning and defuzzification calculation, correcting the pulse duty ratio reference value to obtain a pulse duty ratio smooth value, carrying out single-step variation constraint on the pulse duty ratio smooth value to obtain a pulse duty ratio actual value, and outputting the pulse duty ratio actual value to a pulse electromagnetic valve to control water flow. The invention can effectively avoid the problem of output jump of the traditional fuzzy control in the boundary area and ensure continuous and stable control of water flow.

Inventors

QING WENHUI
SHI FENG
ZHOU XIAOHUAN

Assignees

宁波天鹰电器有限公司

Dates

Publication Date: 20260512
Application Date: 20260410

Claims (10)

1. A water flow control method for a pulsed electromagnetic valve, comprising: Acquiring the upstream water pressure, the downstream water pressure, the actual flow and the target flow of the pulse electromagnetic valve, and preprocessing the acquired original data to obtain the pressure difference and the control requirement; inputting the pressure difference and the control requirement to a fuzzy controller, and generating a pulse duty ratio reference value through fuzzification processing, fuzzy rule reasoning and defuzzification calculation; Correcting the pulse duty ratio reference value to obtain a pulse duty ratio smooth value, performing single-step variation constraint on the pulse duty ratio smooth value to obtain a pulse duty ratio actual value, and outputting the pulse duty ratio actual value to a pulse electromagnetic valve to control water flow; The method for calculating the pulse duty cycle smooth value comprises the steps of calculating a time sequence boundary sensitivity value based on a pressure difference, a preset boundary pressure difference value of a fuzzy set and a preset sensitivity adjustment coefficient, calculating dynamic membership of the pressure difference in each fuzzy set based on the time sequence boundary sensitivity value and the original membership of the pressure difference in each fuzzy set, finding out each activated rule according to a preset fuzzy rule base, the pressure difference and the control requirement in the preset original membership of each fuzzy set, obtaining original activation intensity and reconstruction activation intensity of each activated rule, calculating a smooth weight coefficient based on the difference degree of the reconstruction activation intensity and the original activation intensity and a preset weight adjustment coefficient, calculating a weighted average value of the reconstruction activation intensity of each activated rule, and carrying out weighted fusion on pulse duty cycle reference value and the weighted average value based on the smooth weight coefficient to obtain the pulse duty cycle smooth value.
2. The water flow control method for the pulse electromagnetic valve according to claim 1, wherein the fuzzy controller takes pressure difference and control requirements as input variables and takes a pulse duty ratio reference value as output variables, and the fuzzification processing adopts a triangle membership function and a trapezoid membership function to map the input variables to a preset fuzzy language variable set, namely a fuzzy set.
3. The water flow control method for the pulse electromagnetic valve according to claim 2, wherein fuzzy rule reasoning is based on a preset fuzzy rule base, for each rule in the fuzzy rule base, the minimum value of the original membership of the pressure difference in the rule and the original membership of the control requirement is selected as the original activation strength of the rule, defuzzification calculation adopts a gravity center method, and a pulse duty ratio reference value is calculated according to the original activation strength of each rule and the gravity center position of membership functions of output variables.
4. The method of claim 1, wherein the calculating the time sequence boundary sensitivity value comprises calculating absolute differences between the differential pressure and boundary differential pressure values of each fuzzy set, multiplying the smallest absolute difference by a preset sensitivity adjustment coefficient to obtain a second product, calculating an exponential function value of a negative value of the second product, and taking a difference between 1 and the exponential function value as the time sequence boundary sensitivity value.
5. The method for controlling water flow of a pulse electromagnetic valve according to claim 1, wherein the calculation method of the dynamic membership of the differential pressure in each fuzzy set comprises the steps of multiplying the original membership of the differential pressure in the fuzzy set with a time sequence boundary sensitivity value to obtain a third product for each fuzzy set, calculating an average value of the original membership of the differential pressure in all activated fuzzy sets, wherein the activated fuzzy sets refer to the original membership of the differential pressure in the fuzzy set as not 0, calculating a difference value of 1 and the time sequence boundary sensitivity value, multiplying the difference value with the average value to obtain a fourth product, and taking the sum of the third product and the fourth product as the dynamic membership of the differential pressure in the fuzzy set.
6. The water flow control method for the pulse electromagnetic valve according to claim 1, wherein the reconstructed activation strength of the rule is the minimum value of dynamic membership of a pressure difference in the rule and original membership of a control requirement, the calculation method of the smoothing weight coefficient comprises the steps of adding original activation strengths corresponding to all the activation rules to obtain a second sum value, calculating absolute differences of the reconstructed activation strength and the original activation strength of each activation rule, taking the sum of the absolute differences of all the activation rules as a third sum value, calculating a ratio of the third sum value to the second sum value, multiplying the ratio by a preset weight adjustment coefficient to obtain a fifth product, calculating an index function value of a negative value of the fifth product, and taking the difference of 1 and the index function value as the smoothing weight coefficient.
7. The water flow control method for a pulse electromagnetic valve according to claim 1, wherein the weighted fusion of the pulse duty ratio reference value and the weighted average value based on the smoothing weight coefficient includes weighting a gravity center position of a membership function of an output variable in an activation rule as a weight, weighting a reconstructed activation strength of the rule as a pulse duty ratio reconstruction value, calculating a product of the pulse duty ratio reconstruction value and the smoothing weight coefficient as a sixth product, calculating a difference value of 1 and the smoothing weight coefficient, and taking a product of the difference value and the pulse duty ratio reference value as a seventh product, and taking a sum of the sixth product and the seventh product as a pulse duty ratio smoothing value.
8. The water flow control method for the pulse electromagnetic valve according to claim 1, wherein the step-by-step variation constraint on the pulse duty smoothing value comprises the steps of calculating an allowable maximum step-by-step duty absolute variation based on a time sequence boundary sensitivity value, obtaining an actual pulse duty of the pulse electromagnetic valve, taking a sum of the actual pulse duty and the maximum step-by-step duty absolute variation as an actual pulse duty value when a difference between the pulse duty smoothing value and the actual pulse duty is larger than the maximum step-by-step duty absolute variation, taking the difference between the actual pulse duty and the maximum step-by-step duty absolute variation as an actual pulse duty value when the difference between the pulse duty smoothing value and the actual pulse duty is smaller than a negative value of the maximum step-by-step duty absolute variation, and taking the pulse duty smoothing value as the actual pulse duty value when the difference between the pulse duty smoothing value and the actual pulse duty does not meet the two conditions.
9. The method of claim 1, further comprising obtaining an actual pulse frequency of the pulsed electromagnetic valve after the single-step variation constraint on the smoothed pulse duty cycle value, and adjusting the actual pulse frequency based on the time-series boundary sensitivity value.
10. A water flow control system for a pulsed electromagnetic valve, comprising a processor and a memory, the memory storing computer program instructions which, when executed by the processor, implement a water flow control method for a pulsed electromagnetic valve according to any one of claims 1-9.

Description

Water flow control method and system for pulse electromagnetic valve Technical Field The invention relates to the technical field of water flow control. In particular to a water flow control method and system for a pulse electromagnetic valve. Background The pulse electromagnetic valve is used as a core executing element of a fluid control system and is widely applied to the fields of industrial production, building water supply, agricultural irrigation and the like. The accurate water flow control has key effects on ensuring the running efficiency of the system, reducing the energy consumption and prolonging the service life of equipment. In practical application, the working condition of the system is changed frequently, and the water pressure fluctuates frequently, which puts higher demands on the adaptability and stability of the control system. In the prior art, the water flow control of the pulse electromagnetic valve mainly adopts methods such as PID control, fuzzy logic control and the like. PID control is good under stable working condition, but when facing the complex environment of frequent fluctuation of water pressure, parameter setting is difficult, and adaptability is not enough. Although the fuzzy logic control improves the robustness of the system to a certain extent, the inherent defect exists in the fuzzy set boundary area that when the system pressure difference slightly fluctuates near the fuzzy set boundary, the output of the controller can jump between adjacent rules due to the discrete characteristic of the fuzzy rules, so that the pulse duty ratio is discontinuously changed, and further the water flow oscillation is caused. This phenomenon is particularly prominent in application scenes such as building water supply systems where water pressure changes frequently, and affects control accuracy and system stability. Therefore, there is a need in the art for a water flow control method and system for a pulsed electromagnetic valve to solve the above-mentioned problem of unstable control of water flow in the prior art. Disclosure of Invention In order to solve the technical problem that the control of water flow is unstable in the prior art, the invention provides the following aspects. In a first aspect, a water flow control method for a pulsed electromagnetic valve, comprising: Acquiring the upstream water pressure, the downstream water pressure, the actual flow and the target flow of the pulse electromagnetic valve, and preprocessing the acquired original data to obtain the pressure difference and the control requirement; inputting the pressure difference and the control requirement to a fuzzy controller, and generating a pulse duty ratio reference value through fuzzification processing, fuzzy rule reasoning and defuzzification calculation; Correcting the pulse duty ratio reference value to obtain a pulse duty ratio smooth value, performing single-step variation constraint on the pulse duty ratio smooth value to obtain a pulse duty ratio actual value, and outputting the pulse duty ratio actual value to a pulse electromagnetic valve to control water flow; The method for calculating the pulse duty cycle smooth value comprises the steps of calculating a time sequence boundary sensitivity value based on a pressure difference, a preset boundary pressure difference value of a fuzzy set and a preset sensitivity adjustment coefficient, calculating dynamic membership of the pressure difference in each fuzzy set based on the time sequence boundary sensitivity value and the original membership of the pressure difference in each fuzzy set, finding out each activated rule according to a preset fuzzy rule base, the pressure difference and the control requirement in the preset original membership of each fuzzy set, obtaining original activation intensity and reconstruction activation intensity of each activated rule, calculating a smooth weight coefficient based on the difference degree of the reconstruction activation intensity and the original activation intensity and a preset weight adjustment coefficient, calculating a weighted average value of the reconstruction activation intensity of each activated rule, and carrying out weighted fusion on pulse duty cycle reference value and the weighted average value based on the smooth weight coefficient to obtain the pulse duty cycle smooth value. Preferably, the fuzzy controller takes differential pressure and control requirements as input variables and takes a pulse duty ratio reference value as output variables, and the fuzzification processing adopts a triangle membership function and a trapezoid membership function to map the input variables to a preset fuzzy language variable set, namely a fuzzy set. Preferably, fuzzy rule reasoning is based on a preset fuzzy rule base, and for each rule in the fuzzy rule base, the minimum value of the original membership of the pressure difference in the rule and the original membership of the control requirement