Three-Dimensional Vector Multimapping-Based Power Split for Single-Stage Multiport Inverter-Fed Motor Drives

Single-stage multiport inverter (SSMI) is an attractive solution for hybrid electric vehicles. However, it is challenging to design the modulation scheme for the SSMI since flexible power split between sources on the dc side together with satisfactory stator current control on the ac side should be achieved simultaneously. To this end, a three-dimensional vector multimapping (3DVM)- based power split strategy is proposed in this article to realize flexible power split while guaranteeing the stator current regulation under unbalanced dc links. In the proposed 3DVM scheme, the asymmetrical 3-D vector space is divided into two symmetrical subspaces to simplify the modulation scheme design under unbalanced dc links, and the reference vector decomposed process provides an additional degree of freedom for power split by regulating the decomposed factors. Subsequently, a direct power control model with respect to decomposing factors is put forward to realize power split between dc-port sources without affecting the stator current control. Moreover, by mapping the decomposed reference vectors to the edges and planes of the subspaces, the switching actions are reduced, which increases the power conversion efficiency. Experiments are carried out to validate the effectiveness and superiority of the proposed scheme.