Optimal Switching Sequence MPC of a Three- Port-Converter for Variable-Speed PMSM With Hybrid Energy Storage

This article presents a model predictive current control strategy utilizing optimal switching sequences for two-level, three-port converters driving an anisotropic permanent magnet synchronous machine (PMSM). These converters are attractive in hybrid energy systems, including fuel cell electric vehicles and hybrid energy storage systems. The proposed control method optimally calculates the switching vectors and duty cycles for both steady-state and transient conditions, including during overmodulation, a scenario that introduces significant optimization challenges. The strategy proposes a simple second stage of control to govern the dc port current, exploiting the redundancy of passive vectors, and eliminating the need for weighting factors to balance the control objectives between the PMSM and the energy storage system, giving absolute priority to the control of the PMSM. Experimental results on a laboratory-scale prototype demonstrate the controller high-dynamic performance in regulating torque, speed, and power transfer across multiple ports, while also maintaining a fixed switching frequency and a well-defined harmonic spectrum.