A Simplified Algorithm of Finite Set Model Predictive Control for Three-Phase CHB-Based BESSs

Cascaded H-bridge (CHB) topology receives wide attention in the battery energy storage systems (BESSs) due to its modular structure. When the finite-set model predictive control (FS-MPC) is applied to handle complex issues of the three-phase CHB-based BESSs, the problem of computation amount is emerging due to its traversal algorithm. In this article, a successive searching algorithm for the FS-model predictive control (MPC) is proposed to simplify the traversal subset. In the three-phase space-vector diagram, the proposed algorithm successively adjusts the searching direction to find the optimal voltage vector, according to the cost functions of the adjacent vector table. Moreover, the candidate vectors of the proposed algorithm are further modified by eliminating repeated vectors and unnecessary searching directions ultimately. The algorithm is readily applicable to the CHB-based BESSs and is also general to other multilevel converters. Theoretical analysis and experimental comparison demonstrate the proposal.