Research on PMSM Speed Control of Rotary Steerable System based on Modified LADRC

Abstract

In response to the complex working conditions of the permanent magnet synchronous motor in the rotary steerable system under multiple sources of disturbance, the traditional Linear Active Disturbance Rejection Control(LADRC) has a large observation burden, hysteresis, and low accuracy due to significant load changes, which affects the adjustment of the drilling tool face angle and trajectory stability. Based on the permanent magnet synchronous motor (PMSM) speed current dual closed-loop vector control system, this paper introduces a disturbance observer to optimize the observation mechanism on the basis of the speed loop LADRC, and proposes an modified LADRC(MLADRC) speed control strategy.A simulation model of underground PMSM speed regulation was built in MATLAB/Simulink, and a comparative simulation was carried out under the conditions of speed step and load sudden changes of different amplitudes. The results showed that the designed disturbance observer could accurately capture load torque sudden changes. MLADRC achieved 0 overshoot under speed step and steady-state error control within ±1RPM. During load sudden changes of 5N·m and 15N·m, the speed fluctuation was smaller, the recovery time was shorter, and the anti-interference performance was better, which is suitable for underground load fluctuation scenarios.The MLADRC proposed in this article effectively solves the observation lag problem of traditional LADRC, providing a feasible solution for the optimization of PMSM speed regulation and the improvement of drilling trajectory stability in rotary directional drilling systems.