A Novel SVPWM Strategy for Open-winding Machine with Low Current Ripples

In this paper, a novel SVPWM strategy for open-winding machine fed by common DC-bus dual two-level 3-phase inverters is proposed to reduce current ripples. In the proposed SVPWM strategy for open-winding, each of six sectors in the space vector plane is further divided into three sub-sectors, in which the optimal effective and zero voltage vector action sequences are found to be different. Consequently, different effective and zero voltage vector action sequences are employed in three sub-sectors. Compared with the conventional SVPWM for open-winding, the proposed SVPWM strategy produces similar current harmonics in low modulation index region, but generates much lower current harmonics in high modulation index region without increasing switching frequency, as confirmed by simulation and experiments. Moreover, a zero sequence control method is proposed to suppress zero sequence current and also verified by experiment results.