Grainger CEME Seminars

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Dynamic Level Selection for Full Range ZVS in Flying Capacitor Multi-Level Converters

Event Type
Grainger CEME
4070 ECEB
Apr 9, 2018   1:00 - 1:50 pm  
Margaret Blackwell




This talk presents a control technique for flying capacitor multi-level (FCML) converters to achieve zero-voltage switching (ZVS) across the full range of duty cycles for applications to high power density and high efficiency power converters. Earlier work made use of variable frequency control to enable ZVS at specific duty cycles in FCML converters, but without the ability to allow ZVS across the full range. The proposed technique uses dynamic level selection and variable frequency control to increase inductor current ripple at duty cycle ranges under which ZVS was previously unattainable. An experimental 5-level FCML prototype has been built using GaN devices on a single-sided PCB to incorporate this control technique. We demonstrate both 4 – and 5 – level operations with ZVS at duty cycles that are not possible with 5 – level operations alone, as well as a dynamic level transition with active capacitor voltage balancing.

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