HIGH PERFORMANCE RESISTANCE EMULATOR BASED ON A BIDIRECTIONAL MULTILEVEL CONVERTER AND GaN DEVICES

Abstract

This work discusses a multilevel bidirectional converter designed to emulate loss free resistors within a future power cable emulator in a large frequency range. The proposed converter is composed of four TType converter legs, interleaved and connected through two interphase transformers. This structure provides an excellent loss distribution and a nine-level voltage is synthesized on its ac port, where only a compact filter is required. Thus, the proposed topology tends to be compact, highly efficient and presents a fast dynamic response. A GaN-based prototype at a rated power of 400 W switched at 250 kHz is built. Experimental results shows that the proposed converter achieves a peak efficiency of 98.5% at a quarter of the rated load reaching 97.1% at full-power.