Research On Control Method Of Continuous Wave Mud Pulser Based On PMSM

With the rapid development of measurement while drilling(MWD)technology,more and more downhole data need to be measured,which requires increasingly faster information transmission efficiency.A Continuous wave mud pulse generator has good application prospect and research value in petroleum engineering field because of faster transmission efficiency and stronger anti-interference ability compared with a traditional positive pulse generator.In this paper,based on the actual industrial application background,the permanent magnet synchronous motor is identified as the rotary valve drive motor of the continuous wave mud pulse generator.The vector control method of surface mounted permanent magnet synchronous motor is introduced.The transformation relationship between three coordinate systems is analyzed.A system control scheme based on vector control strategy is given.A fast non-singular terminal sliding mode surface is designed and combined with a new reaching law design to form a velocity loop sliding mode controller applied to the motor control system.The stability of the system is discussed by using Lyapunov stability criterion,and the excellent performance of the designed fast non-singular terminal sliding mode control algorithm is verified by simulation.Next,a nonlinear state observer for permanent magnet synchronous motor is designed in this paper.First of all,the observability of the permanent magnet synchronous motor system is discussed based on the equation of state of the motor in the two-phase stationary coordinate system.Then a nonlinear observer is designed to realize the estimation of the motor speed.The Lyapunov stability criterion is used to prove that the system has good convergence under the state observer,and the system states can approach the actual value effectively.Finally,the velocity loop fast non-singular terminal sliding mode controller proposed in this paper is incorporated with a nonlinear observer,and the actual value of speed is replaced by the speed estimate of the observer and applied to the continuous wave mud pulse generator motor control system.The stability of the closed-loop system is demonstrated based on the Lyapunov stability criterion.As is indicated by the simulation results.This non-sensor control algorithm has sound steady-state and anti-disturbance performance.The motor rotor speed could converge to the real values quickly.