MPC for Dual-Three-Phase PMSM Drives With Improved Harmonic Suppression Capacity and Torque–Speed Operation Range

Due to much more available voltage vectors (VV), dual-three-phase (DTP) permanent magnet synchronous machine (PMSM) drives are more challenging in selecting the VVs than single-three-phase (STP) ones. The model predictive control (MPC) based on synthetic VVs is an excellent solution. However, its torque-speed operation range and harmonic suppression capacity at high speed are limited by the utilized synthetic VVs. In this paper, the MPC based on long (L) and medium-long (ML) VVs is proposed for DTP PMSM drives, which uses L and ML VVs directly instead of using them to construct synthetic VVs. A restraint strategy based on voltage estimation is designed to reduce the range of VV candidates and computation burden. A selection strategy based on cost functions is developed for the optimal L and ML VVs. In addition, it is verified that the optimization model for duty ratio calculation in the proposed MPC is convex. Thus, the projected quadratic programming (QP) algorithm, used in the STP drives, can be extended and used for duty ratio calculation in the proposed method, with which faster calculation than the discrete enumeration is achieved. Further, it is verified that the QP algorithm is also suitable for other MPCs for DTP PMSM drives whatever VVs are used. By using the L and ML VVs directly, the proposed MPC can not only obtain a wider torque-speed operation range than MPC based on synthetic VVs, but also realize lower current THD at high speed. Finally, experiments are conducted to verify the feasibility and advantages of the proposed method.