Advancements in energy systems and electric vehicles have increased demands for efficient and compact power electronics. High-frequency operation is important for miniaturization of switching power converters since it reduces energy storage requirement and improves transient performance. Wide-bandgap semiconductors allow for efficient high-frequency switching, but full realization of their potential in power electronics requires efficient power-dense high-frequency passive components. Magnetic components such as inductors and transformers, due to their frequency-dependent losses, are increasingly the main bottleneck in improving the density of power converters.
Although incremental improvements in magnetics, and passives in general, are enabling advances in power electronics, the importance of the problem merits consideration of the fundamental performance limits and exploration of alternative passive component technologies. Analysis of various energy storage mechanisms indicates the potential of mechanical storage coupled with a piezoelectric transduction mechanism. Optimally designed piezoelectric and electromagnetic resonators, in ideal scenarios, are capable of orders-of-magnitude higher power density than passive components in use today. Investigation of various practical limitations provides insights into possible technological development for improving the performance of passive components and switching converters.
High-performance resonant tanks and power converters are also presented. First, an integrated LC resonator with a multilayer foil winding demonstrates 50% better performance compared to a similar resonator with a single-layer skin-effect limited winding. Second, an optimally designed integrated LC resonant tank, made of commercial Class I ceramic capacitors, has a sub-m? effective series resistance and incurs only 4.56 W loss, resulting in a 7.42 kW power capability in a small 1.14 cm3 volume. The high performance means that a power converter utilizing these prototype resonators will be limited by the performance of switches rather than by the passive component. Finally, a prototype 48 V to 16 V stacked-ladder converter, with a high active device utilization figure of merit, combined with a small low-loss integrated resonator, provides a peak efficiency of 97.8% and a high power density of 913 W/in3. The theoretical analysis, together with these prototypes, shows the potential for significant improvement in the efficiency and power density of high-frequency switching converters, and the various technological developments required to achieve such improvements.
|Advisor:||Sullivan, Charles R.|
|Commitee:||Levey, Christopher G., Perreault, David J., Stauth, Jason T.|
|School Location:||United States -- New Hampshire|
|Source:||DAI-B 80/04(E), Dissertation Abstracts International|
|Subjects:||Engineering, Electrical engineering|
|Keywords:||High-frequency power conversion, Magnetics, Passive components, Piezoelectricity, Resonant power converters, Resonant tank|
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