Disturbance Rejection Study and Validation of the Control Law for the Guide Vane of Variable Geometry Low Pressure Turbine

During the aeroengine operation, the airflow with the high temperature and pressure acts on the guide vanes of the low pressure turbine (LPT). The guide vanes are subjected to high pneumatic loads. The pneumatic load is transmitted to the adjustment mechanism of the guide vanes. The pneumatic load varies greatly under different operation conditions. Therefore, the adjustment mechanism of the guide vanes has the requirements of the fast response, the low overshoot and zero static error and strong disturbance rejection ability. In this study, permanent magnet synchronous motors (PMSM) are used as the actuators. This study adopts the scheme with multiple PMSMs and the linkage ring. Three drive motors regulate the rotation angle of the guide vanes. Three load motors simulate the pneumatic load disturbance. The drive motors and load motors are arranged crosswise in the circumferential homogeneous manner on the linkage ring, with neighbouring motors spaced 60° apart. The active disturbance rejection control (ADRC) is used instead of the traditional three-loop control structure of angle-speed-current to enhance the disturbance rejection ability of the actuators. The improved synchronization control method with variable deviation coupling is applied to ensure the synchronization of the drive motors. The hardware in the loop (HIL) experimental system is built to verify the feasibility and the real-time performance of the ADRC algorithm. It is verified that the adjustment mechanism of the guide vanes has the fast response speed and the high precision. It can follow the command angle in time. The ADRC and synchronization control algorithms can significantly enhance the disturbance rejection ability and the synchronization respectively. The study provides the technical support for the performance enhancement of the variable geometry turbine (VGT).