Duty Ratio Based Model Predictive Flux Control With Direct Switching-State Selection for Induction Motor Drives

This article presents a low-complexity model predictive flux control (MPFC) scheme for induction motor drives that achieves the ripple-reduction benefits of duty-ratio-based MPFC with a reduced computational burden. The inverter switching state is obtained directly in the three-phase (\boldsymbol{abc}) frame from the signs of resistance-compensated per-phase stator flux errors, and the adjacent active vector is determined by a one-bit leg toggle that minimizes projection loss. A constant-projection boundary then selects either the zero vector or the adjacent active vector as the secondary voltage vector in each sampling interval. Duty ratios are computed from the scalar projections, and the selected vectors are applied symmetrically, resulting in two commutations per sampling interval and a near-constant switching frequency. The proposed MPFC algorithm is validated against both simulation and experimental results.