The seminar explores high-frequency resonant power conversion, focusing on LLC converters, which meet the demands for miniaturized, efficient converters in modern power electronics. This three-hour tutorial offers a comprehensive understanding of LLC converters, emphasizing the most important details (magnetic optimization, device selection, PCB layout and thermal management) for their efficient design and practical implementation. The first section covers the fundamental principles of single-phase LLC converters, their advantages and disadvantages in comparison with traditional PWM topologies, and advanced design procedures to maximize their potential. Attendees will learn techniques for implementing these converters effectively. A case study of a 1 MHz, 1 kW, 20 kW/l, 270-28 V DC/DC converter used in aircraft applications will illustrate this type of converters, showcasing its performance and practical implementation, and magnetic and PCB optimization will be addressed in detail. In the second section, novel three-phase converter topologies derived from LLC converters are introduced. These configurations allow the use of star-polygon transformers and stacked cells to achieve higher voltage step-down DC/DC conversion, easing the specifications of the transformer and the inductor. Challenges in integrated magnetic design, thermal management and current sharing are addressed, highlighting the multiphase approach as a viable alternative to single-phase parallelization.
