Modeling And Performance Analysis Of Electric Valve Positioning System

Regulating valves have become an indispensable terminal control element in the automation industry due to their wide variety,strong adaptability,safety and reliability.Pneumatic control valves have outstanding characteristics such as stable performance,easy control,easy maintenance,and high cost performance,and are widely used.In the field of modern automation industrial process control.In the 13th Five-Year Plan,the intelligent control of control valves was proposed.The 14th Five-Year Plan put forward higher requirements.To achieve high-quality regulation requirements for pneumatic control valves,a valve positioning system is mainly used.It is called the valve servo positioning system,which has the function of positioning the valve,which can overcome the friction between the valve stems and the uneven reaction force caused by the changes in the temperature and pressure of the pipeline fluid,so as to make The valve stem responds quickly,achieves accurate positioning,and controls the flow rate and flow rate.Modeling and analyzing the valve automatic positioning system to improve its automatic control performance can effectively improve the control accuracy,system response speed and control flexibility of the automatic control valve.To study the valve positioning system,in addition to the technical level of research and development and innovation and expansion,you can also use computer simulation technology to build a model of the system,study its performance,control methods,etc.to promote the performance of the system,which is important for the control of regulating valves and valve positioning The optimization of the system is of great significance.Based on the modeling of the valve positioning system,this paper studies the influence of the change of positioning system parameters,and lays the foundation for the optimization and improvement of the valve positioning systemFirst,the goal is to establish a simulation model of the valve positioning system.Analyze the working process of the valve positioning system,study the components of the entire system and the working principle of each component,and determine the modeling object.his system is mainly composed of intelligent valve positioners,pneumatic membrane actuators and other components.The valve positioner includes electrical converters,relays,and valve position feedback mechanisms.For the output characteristics of the torque motor in the electrical converter,based on Maxwell simulation,the torque equation is fitted in MATLAB,and the other components are established on the basis of the mathematical model of the working principle.In Simulink,the mathematical model of each component is integrated into a simulation model in a modular manner,and the unknown parameters are determined through the product nameplate description,data search,and actual application conditions.Secondly,it analyzes and studies the influence of the change of the main parameters of the valve positioning system on the performance of the system.This article mainly focuses on the influence of nozzle inner diameter change,relay flow characteristic change and air source pressure change on the entire system,and obtains the optimal parameter value,which provides a reliable theoretical basis for system optimization and structural design.In order to verify the accuracy of the simulation model,based on equipment such as valve positioners and pneumatic membrane actuators,an experimental platform is built with the help of data acquisition cards,sensors,etc.,and LABVIEW software is used to achieve data collection and storage.The experimental measurement is performed on different step signals.The response of the next system.By comparing the experimental curve and the simulation curve,it is confirmed that the simulation model can basically reflect the actual system operation.Based on the accurate simulation model,the response of the system under different parameters was tested,and it was found that if the inner diameter of the nozzle is too large or too small,the linear area of the positioning system will be reduced.To consider the overall linearity of the positioning system,the inner diameter of the nozzle hole is general The value is 0.8～1.0mm;as the pressure of the air source increases,the maximum gas mass flow rate of the relay will increase,and the linearity of the control will increase.At the same time,the change of the air source pressure will affect the response time of the entire system.The greater the pressure,the faster the response time.