Model Predictive Direct Position Control Strategy Based on Point-to-Point Trajectory Planning for Fast Response of High-Inertia PMSM Servo System

Permanent magnet synchronous motors (PMSMs) with large inertia require more precise torque control and longer start-stop buffer times. However, traditional proportional-integral (PI) control can only limit speed within upper and lower bounds, and the cascaded servo system suffers from reduced control accuracy due to bandwidth attenuation, leading to significant overshoot during rapid position response control. This article proposes a model predictive direct position control (MPDPC) strategy based on S-curve point-to-point trajectory planning. It abandons the traditional cascade control structure and complex space vector pulsewidth modulation (SVPWM) technology. Instead, it adopts a rolling optimization approach, directly embedding multiple complex constraints such as position, speed, and current into the optimization solution process. Predictions are updated in real-time, and the optimal vector is selected within each sampling cycle. Leveraging its high control bandwidth characteristics, this strategy exhibits more sensitive adjustment capabilities for position error, enables real-time planning of the rotor trajectory, and achieves continuous acceleration changes by controlling jerk. Consequently, it attains the control objectives of real-time speed control, fast position response, and zero overshoot. Simulation and experimental results comparing position, velocity, and angular acceleration response curves under different control strategies verify the superiority of the proposed strategy in dynamic performance.