Hybrid Multivector FCS–MPC for Six-Phase Electric Drives

Standard finite control set model predictive controllers (FCS–MPC) suffer from a deteriorated current quality when applied to multiphase drives. This problem has been recently mitigated with the concept of virtual voltage vectors. Its application ensures reduced current harmonics by limiting the
x–y
voltage injection. An intensive research effort has been done seeking for the best vector combination to provide an optimized performance in FCS–MPC. On one hand, multivector strategies including a null vector refine the effective voltage production with enhanced current quality but the dc-link utilization decreases. On the other hand, the exclusive use of large virtual vectors (LVVs) ensures a higher dc-link utilization at the price of a poorer current quality at low-voltage operation. This article first proposes an extended version of multivector strategies using a zero vector by including a quartet of voltage vectors. The usage of five switching states into the predictive approach (MV5–MPC) improves the current quality but still lacks a suitable utilization of the dc-link voltage. To overcome this limitation, the proposed MV5–MPC is combined with LVV–MPC to provide a hybrid solution that simultaneously achieves a higher current quality and a satisfactory dc-link utilization. Experimental results confirm the effectiveness of the proposal.