Simulation And Experiment Research Of The Direct-drive Electro-hydraulic Actuator Of Regulating Valves

Power station regulating valves, used for continuously adjusting flow of the pipeline medium, are the terminal links of power plant automatic control system. In this paper, it is found through the survey that there are both advantages and disadvantages inthe three kinds of valve actuatorswidely used at present: pneumatic, electric and hydraulic actuators. With the development of power regulating gradually to automatic and intelligent directions, such a valve actuator product is urgently needed, which integrates the advantages of the above three kinds of valve actuators. Direct Drive Volume Controlsystem, having the advantages of small integration, strong ability to resist load disturbance, high efficiency and saving energy, and power availability, brings hope for the innovation of new regulation valve actuator product.In this paper, element specifications are, first of all,chosen according to the technical parameters of given valve actuators. Then integration and no-pipe design of general structure of DDVC actuator, including motor, pump, Central manifold, pressuredsealed oil tank, single rod symmetrical hydraulic cylinder, and sensing instruments, are accomplished.After that, the AMESim model of DDVC pump control cylinder power mechanism is established according designed DDVC hydraulic system principle, including separate simulations for the sub-models of displacement pump, Pilot check valveand so on, and the performances of closed loop are deeply analyzed.On this basis, the AMESim model is co-simulated with the tuned transfer function model of the AC permanent magnet synchronous motor by AMESim/Simulinkinterface,in order to compound the composite model of DDVC system. The simulation results, compared withtypicaltransfer function model of DDVC system, have basically unchanged frequency response, but dead zone nonlinear phenomenon as actuators change directions occurs.According the simulation features of the composite model, state equation of DDVC system is established and discreted. The structure parameter perturbation and external load disturbance are analyzed. In order to realize full state feedback of control system,lineardiscrete integral tracking differentiator is designed, estimating the velocity and acceleration of actuators according the position measurement signal, and analyzing the affect of different parameters on the differentiator performance. The basic conditions,reaching law, control law and so on of discrete sliding mode control strategy application are analyzed, and the sliding mode switching function are designed through pole assignment method. And then, the discrete sliding mode controller model with differentiator is constructed in Simulink, the feasibility of which is preliminarilyverified through the simulation.In the end, the complete DDVC electric control system is set up. The real-time control program of DSP microprocessor is written in CCS Integrated development platform. The PC interface used for sample and control is constructed In Lab VIEW. The communication between the two is achieved with the help of Ethernet. Completely consistent parameters configuration with the simulation phase is chosen, and the simulation model and differentiator model are verified. In final, the sliding mode controller performance is tested, and basically consistent conclusions with simulation result are gained. Superiorities of sliding model control compared with PID control, in system quickness, tracking accuracy and compensation action on dead zone nonlinear, are verified.