Mitigation of Common-Mode Voltage in 3L-VSI-Fed Dual Three-Phase PMSM Drives Using Model Predictive Control

In this article, a novel finite-control-set model predictive control (FCS-MPC) method is proposed for the voltage-source inverters (VSIs)-fed dual three-phase (DTP) permanent-magnet synchronous motor (PMSM) drive with two isolated neutral points, aiming at mitigating the common-mode voltage (CMV) in the drive system. The design is carried out for three-level topology. With the additional control freedom of six-phase PMSM drive, the zero CMV (ZCMV) voltage vectors can be constructed. The primitive voltage space vectors are synthesized after using vector space decomposition (VSD) transformation at first. The characteristics of these voltage vectors are analyzed, and the ZCMV vectors are selected as the candidates in the next step. In consequence, the FCS-MPC method is proposed for the drive system using these ZCMV vector candidates. For the large number of vectors for three-level topology and the requirement to avoid PN jumps, a two-step vector synthesis method is proposed for simplified procedure. In addition, a universal suppression method is designed to effectively suppress the influence of dead-time nonlinearity on the proposed CMV elimination strategy. Finally, the experiments are given to verify that the proposed FCS-MPC method and dead-time effect suppression method can mitigate the CMV effectively and enable the drive system the good operation performance.