Six-phase machine conversion system with three-phase and single-phase series converters

This paper presents two conversion systems based on six-phase machine (SPM) and three-phase and single-phase series-connected converters without isolation transformers. Configuration 1 can be used with induction (IM) or permanent magnet synchronous (PMSM) machines, while configuration 2 is partially reversible and is more indicated for permanent magnet synchronous machines. Compared with the conventional back-to-back nine-leg conversion system, the proposed converter permits to reduce the power processed by the converter switches, the dc-link voltage and the harmonic distortion or the switching frequency. Furthermore, the proposed configurations guarantee the feasibility of the system when highpower applications are considered. The complete analysis of the systems, including the PWM techniques, is presented and compared with the conventional one. The simulation and experimental results are presented.