A Sensitivity-Based Model Predictive Current and Speed Control Scheme for Permanent Magnet Synchronous Motor Drives with Reduced Current Total Harmonic Distortion and Torque Ripple

Abstract

This paper presents a sensitivity-weighted dual-objective finite-control-set Model Predictive Current and Speed Control (MPCSC) scheme for Permanent Magnet Synchronous Motor (PMSM) drives. The proposed cost function jointly penalizes dq-axis current tracking errors and rotor-speed deviation. A closed-form weighting factor is derived from the relative sensitivities of current and speed to an identical inverter voltage-vector perturbation, reducing the reliance on heuristic tuning. At each sampling instant, eight feasible two-level inverter voltage vectors are evaluated and the minimizer is applied in the next control interval. MATLAB/Simulink simulations of a 1.5 kW PMSM drive (Ts = 10 µs) show that, at 70 rad/s and half-load, the proposed MPCSC reduces phase-current Total Harmonic Distortion (THD) from 20.10% to 14.80% and decreases peak-to-peak torque oscillation from 6.2 Nm to 4.7 Nm. Under load steps and speed-reversal tests, the proposed controller also mitigates speed dips and torque/current peaks. The measured worst-case execution time increases from 2.5 µs to 2.8 µs, remaining within 28% of the 10 µs computation budget, which supports real-time DSP feasibility.