A Simplified Two-Vector Approach for Common-Mode Voltage Reduction in Model Predictive Control Drives of Permanent Magnet Synchronous Motor

Abstract

In this study, a model predictive control (MPC) strategy is proposed for electrical drivers of the permanent magnet synchronous motors (PMSMs). The proposed method is designed not only to ensure optimal current and torque control but also to significantly reduce common-mode voltage (CMV). CMV is considered one of the main challenges in motor drive systems because it can lead to increased electromagnetic interference, bearing leakage currents, and a reduced lifetime of electrical and mechanical components. To address this issue, a simplified two-vector MPC method that applies two nonzero switching vectors at each sampling instant was developed. This approach was designed to improve stator current total harmonic distortion (THD) while reducing computational burden and system complexity. First, the three-phase two-level inverter and PMSM dynamics are modeled, and then an MPC controller is designed to simultaneously maintain high-quality current/torque control and reduce CMV. The effectiveness of the proposed simplified two-vector approach is validated through MATLAB/Simulink simulations and experimental implementation on a digital signal processor–based hardware platform. The experimental results confirm that the proposed simplified two-vector MPC method results 40% reduction of CMV and 25.5% reduction of stator current THD in comparison with the conventional MPC drive.