Multi-channel Electric Opening Valve Control System Design And Its Fault Detection Method Research

Electric opening valves are key equipment in pipeline systems and are widely used in chemical production,oil and gas extraction and other fields.Traditional electric valve controllers are difficult to meet current industrial control requirements due to their few functions,single control mode,large size and poor opening control accuracy.For example,in flow control scenarios,traditional controllers are too dependent on flow measurement devices and have problems with long adjustment times and unstable flow control.In addition,some traditional controllers do not have fault detection function,which is difficult to apply in scenarios with high security requirements.At present,the electric opening valve controller develops towards light weight,intelligence and high precision.A high precision opening control system can effectively improve the efficiency of the medium transmission in the pipeline system,while a stable and reliable fault detection system can help extend the life of the valve actuator,therefore,the opening control system and fault detection system of the electric opening valve have also become the focus of research.This thesis has designed a control system for an electric opening valve with a dual MCU + CPLD as the core.Its features are: it supports various working modes such as local control and remote control,and the number of valve channels is easy to expand;it adopts a fuzzy PID control algorithm,which effectively improves the adjustment time and overshoot of the system;the fault detection subsystem adopts a fault feature extraction technique and combines with KNN algorithm,which can identify a variety of valve fault states.In The main research contents of this thesis are as follows.1)Based on the simulation analysis of computer fluid dynamics and Fluent software,the velocity distribution of the internal flow field and the outlet flow rate of the valve under different values of differential pressure and opening,and the three-dimensional data table of differential pressure,opening value and outlet flow rate are established.The control of valve opening is the key to regulating the flow rate,furthermore,the valve opening control model is established and the design of fuzzy PID controller is completed.Simulation of the valve outlet flow control in Simulink environment by combining the three-dimensional data table of differential pressure,opening value and outlet flow rate,the opening control model and the fuzzy PID controller;2)Analyze the functional requirements,technical specifications and main technical difficulties of the electric opening valve control system,and complete the overall design of the control system based on the dual MCU + CPLD architecture.Afterwards,the hardware circuit design is carried out,including the design of the circuit schematic and the corresponding PCB diagram,and the software design is completed under the Keil5 development environment;3)The valve vibration signal was collected,and the vibration signal was analyzed and processed in the Matlab software environment based on the signal processing technique of wavelet packet transform,by extracting the fault feature parameters and combining with KNN classification algorithm for fault sample classification test.In addition,a fault detection system upper computer was developed based on C#;4)Build an experimental environment to conduct experimental tests on the function of each module of this control system,the accuracy of opening control and the effect of fault detection,which provides a direct basis for the next improvement and optimization of the electric opening valve control system.The test results show that the electric opening valve control system designed in this thesis can meet the expected functional requirements,the opening control accuracy reaches within ±1%,the fault detection system can effectively identify a variety of fault states,and has certain engineering practical value.