A Carrier-based PWM to Achieve Minimum Flux of Coupled Inductor for Interleaved Three-level Inverters

Paralleling and interleaving power converters allows higher power rating as well as reduced output harmonics. However, circulating currents occur in the parallel interleaved converters and degrade system performance. Coupled inductor is usually used to suppress high frequency circulating currents. The coupled inductor design is strongly impacted by the maximum flux linkage in the magnetic core of coupled inductor. This paper aims to minimize the high frequency flux linkage of coupled inductor for parallel interleaved three-level inverters. A carrier based PWM which achieves lowest coupled inductor maximum flux linkage for all modulation indexes is proposed. The coupled inductor flux linkage reduction of the proposed modulation is verified by experimental results on two parallel interleaved three-level active neutral point clamped inverters.