A Robust Decoupled Predictive Control With Resonance Suppression and CMV Elimination for a Four-Leg Inverter Fed Induction Motor Drives

This article proposes a predictive control scheme for a four-leg inverter fed induction motor (IM) drive with a motor-side LC filter. The third-order (LCL) filter/load structure poses control challenges. These challenges are addressed in the proposed scheme by separating the traditional finite set model predictive control (FS-MPC) into two independent stages: controller and modulator. To avoid the trade-offs typically associated with FS-MPC, the two stages are then separately designed to achieve different objectives. The controller stage provides optimal control with integral action at the fundamental frequency, resulting in excellent tracking performance and low sensitivity to modeling errors and disturbances. The modulator stage features a feedback quantizer (FBQ) with a feedback notch filter. This provides low harmonic distortion of the load current, suppresses resonances, and eliminates common mode voltage (CMV). The proposed ac drive solution is validated by simulation and experiment.