New Multilevel Converters With Coupled Inductors: Properties and Control

In the paper, a new five-level (5L) converter is presented. It is called 5L-active-neutral-point-clamped with coupled-inductor (5L-ANPC-CI) and consists of a three-level bidirectional (3L-B) commutation cell connected to two parallel basic commutation cells. The proposed topology can be seen as two cascaded current stages controlled at different frequencies. The high-current stage is specific to the 3L-B cell controlled at low-frequency, while the low-current stage corresponds to the parallel cells with coupled-inductor controlled at high-frequency (HF). Due to this advantage, the new converter appears as a useful solution to increase the output current, while the switched current through the HF power devices is reduced. The operation principle of the new structure is verified by simulations both for single- and for three-phase topologies. Experimental results for single-phase 5L-ANPC-CI converter on a low-voltage test bench are also provided to validate the proper operation of this concept.