Abstract:
Switching loss is a major factor in determining the performance of modern power electronics converters. Soft-switching-based converters are, consequently, developed to mitigate this loss mechanism. The phase-shifted full-bridge (PSFB) converter is such a converter that is appealing in many high-power applications, such as datacenters. Understanding the underlying principles of the zero-voltage switching (ZVS) mechanism within this converter and fine-tuning the corresponding system parameters are necessary to achieve higher efficiency and power density. Despite the importance of this subject, there is a lack of broad studies that investigate the interdependence effects of system parameters on ZVS realization and modeling the ZVS transitions accordingly. This dissertation identifies the switching deadtime values as parameters of particular sensitivity for this topology. Subtle changes to the switching deadtime values can result in dramatic changes to the overall system efficiency, especially for certain combinations of other system parameters. This dissertation provides a set of empirically validated analytical tools that provide new insight into the interdependence of these parameters and offer useful guidance to practitioners seeking to maximize the performance of this topology, especially for implementations that utilize Wide Band-Gap (WBG) semiconductors in their structure. A set of practical guidelines is also provided to assist with fine-tuning this topology for maximum performance. Moreover, these sets of analytical tools are employed in this dissertation to design and implement a 10-kW, SiC-based, synchronous-rectified PSFB converter, which is optimized for efficiency and power density.
