48/72-step voltage double three-level converters coupled with line-side reactors

摘要

A novel 48- or 72-step voltage power converter system topology without using bulky input transformers is proposed. The system consists of three line-side interphase reactors, two three-level voltage-source power converters and an additional single-phase converter with a small single-phase transformer. The two main converters operate at the power line frequency and the additional converter operates at a frequency of six times the line frequency. The resultant voltages have a smaller total harmonic distortion of 3.97% for the 48-step operation or 2.59% for the 72-step operation.