Synchronous-Conduction-Mode Tapped-Inductor Buck Converter for Low-Power, High-Density Application
| dc.contributor.author | Yeh, Chih-Shen | en |
| dc.contributor.committeechair | Lai, Jih-Sheng | en |
| dc.contributor.committeemember | Koh, Kwang-Jin | en |
| dc.contributor.committeemember | Li, Qiang | en |
| dc.contributor.department | Electrical and Computer Engineering | en |
| dc.date.accessioned | 2018-01-11T20:57:13Z | en |
| dc.date.available | 2018-01-11T20:57:13Z | en |
| dc.date.issued | 2017-11-06 | en |
| dc.description.abstract | General-purpose step-down converter is essential in electronic system for processing energy from high-voltage rail to low-voltage circuits. The applications can be found at the auxiliary supplies in automobile, industrial and communication systems. Buck converter is a common circuit topology to fulfill step-down conversion, especially in low-power application since it is well-studied and straightforward. However, it suffers from low duty cycle under high step-down condition, and typically operates in continuous conduction mode (CCM) that generates large switching loss. On the other hand, as an extension of the buck converter, tapped-inductor (TI) buck converter has larger duty cycle while maintaining the structural simplicity. Therefore, the main objective of this thesis is to explore the potential of TI buck converter as a wide conversion range, high power density and high efficiency topology for low power application. To achieve high efficiency at switching frequency of MHz-level, synchronous conduction mode (SCM) is applied for turn-on losses elimination. The operation principle and power stage design of SCM TI buck is first introduced. The design of high switching frequency coupled inductor is emphasized since its size plays a critical role in power density. Loss breakdown is also provided to perform a comprehensive topological study. Secondly, detailed zero-voltage-switching (ZVS) condition of SCM TI buck is derived so that the converter does not experience redundant circulating energy. The experimental results of 15-W SCM TI buck converter prototypes are provided with 90.7% of peak power stage efficiency. The size of coupled inductor is down to 116 mm3. To enhance light-load efficiency, a variable frequency control scheme based on derived ZVS conditions is implemented with the switching frequency ranging from 2 MHz to 2.9 MHz. | en |
| dc.description.abstractgeneral | General-purpose step-down converter is essential in electronic system for processing energy from high-voltage rail to low-voltage circuits. The applications can be found at the auxiliary supplies in automobile, industrial and communication systems. Typically, the ultimate goals of general-purpose step-down converter are versatility, high efficiency and compact size. Recently, tapped-inductor (TI) buck converter is studied since it could overcome the drawback of commonly used buck converter under high step-down conversion. Therefore, the potential of TI buck converter as a general-purpose step-down converter candidate is explored in this thesis, including control method, hardware design, etc. The thesis verifies that TI buck converter could have compact size while remaining efficient and adaptable. | en |
| dc.description.degree | Master of Science | en |
| dc.format.medium | ETD | en |
| dc.identifier.uri | http://hdl.handle.net/10919/81722 | en |
| dc.language.iso | en_US | en |
| dc.publisher | Virginia Tech | en |
| dc.rights | Creative Commons Attribution-ShareAlike 3.0 United States | en |
| dc.rights.uri | http://creativecommons.org/licenses/by-nc-sa/3.0/us/ | en |
| dc.subject | coupled inductor | en |
| dc.subject | zero-voltage switching | en |
| dc.subject | non-isolated dc-dc converter | en |
| dc.subject | high step-down | en |
| dc.subject | high switching frequency | en |
| dc.subject | low-power application | en |
| dc.title | Synchronous-Conduction-Mode Tapped-Inductor Buck Converter for Low-Power, High-Density Application | en |
| dc.type | Thesis | en |
| thesis.degree.discipline | Electrical Engineering | en |
| thesis.degree.grantor | Virginia Polytechnic Institute and State University | en |
| thesis.degree.level | masters | en |
| thesis.degree.name | Master of Science | en |