Study Of Ring Communication Based Cascaded Resonant Converter Topologies

In the past decades, study of hard-switched converters drew a lot of attention. Such converters are now widely used in electrical drive vehicles integration and for handled devices power outlets in the IT industry. Researchers have considered many topologies; including SiC JFETs based Buck/Boost converters that offer excellent power efficiency amongst hard-switched converters. Input Series/Output Parallel multi converters based on hard-switched topologies were also analyzed and can achieve good input voltage balancing. However very few studies considered the impact of communication delays in such topologies. Moreover resonant converters started recently to be considered in multi-resonant converters as they offer low EMI, high switching frequency and reduce the components stress. Cascaded converters using resonant topologies count today few results discussing their design and performances.This study proposes a design method for cascaded converters based on resonant converters and using ring communication as this protocol offers high reliability with low communication delays. A comparison of the performances with hard switched-based designs will be given (bandwidth, susceptibility to communication delays and dynamics). The results obtained in this thesis show that the system based on LLC sub-converters has a higher bandwidth and faster dynamics as LLC converters work at a higher switching frequency than the Buck/Boost converters. However those advantages are counter-balanced by lower acceptable communication delay and higher power losses induced by the increase in power switches and computing units.