Improved variable-structure cascade ADRC-based model predictive torque control for permanent magnet synchronous motor

To address the issues of degraded compromised dynamic performance and limited robustness and difficulty in calculating the reference flux linkage in traditional model predictive torque control (MPTC) for permanent magnet synchronous motor, this paper proposes an enhanced MPTC scheme integrated with an improved variable-structure tiered active disturbance rejection controller (VS-TADRC). The scheme features three key innovations: First, simplification of reference flux linkage calculation. To reduce the computational complexity associated with calculating reference flux linkage from reference torque in conventional MPTC, a mathematical model based on the air-gap flux linkage oriented axis is introduced. This enables direct calculation of reference flux linkage, significantly reducing computational burden. Secondly, enhanced speed-loop robustness. To mitigate the limited robustness of PI controllers in traditional MPTC, a tiered active disturbance rejection controller (ADRC) is employed to replace the PI controller in the speed loop, It addresses the difficulty of a single ESO in handling complex disturbances, thereby enhancing the dynamic performance of MPTC. Finally, optimized disturbance rejection for ADRC. Addressing the issue in conventional ADRC where the nonlinear state error feedback (NLSEF) component exhibits inadequate disturbance rejection capability due to simplified decoupling and a heavy reliance on the design of nonlinear functions, a novel variable-structure mechanism is adopted to replace the NLSEF. This effectively improves control accuracy and further strengthens the overall robustness of the control system. Experimental results demonstrate significant performance improvements: current overshoot is reduced by approximately 18.16%, and torque overshoot is reduced by approximately 21.92%.