Title page for ETD etd-06062008-164601


Type of Document Dissertation
Author Sabaté, Juan A
URN etd-06062008-164601
Title Zero-voltage switched resonant and PWM converters : design-oriented analysis and performance evaluation
Degree PhD
Department Electrical Engineering
Advisory Committee
Advisor Name Title
Lee, Fred C. Committee Chair
Borojevich, Dushan Committee Member
Cho, Bo H. Committee Member
Jovanovic, Milan M. Committee Member
Riess, R. Dean Committee Member
Keywords
  • DC-to-DC converters
Date of Defense 1994-04-26
Availability restricted
Abstract
The relative perfonnance evaluation of the different alternatives of bridge topologies with zero-voltage switching is presented. A design-oriented analysis is developed to optimize implementation of the converters in tenns of efficiency. Efficiency optimization requires minimizing the circulating currents which are directly proportional to the reactive energy required by the resonant tank. The comparison of the different converters is based on the reactive energy required for ZVS. The study considers resonant converters with conventional variable frequency control and with phase-shift control, and the zerovoltage- switched full-bridge PWM converter (ZVS-FB-PWM). Also, a systematic procedure to determine all possible resonant converters with two or three reactive elements is presented, and the design-oriented analysis used to classifY them according to their properties.

The analysis for the resonant converters uses the fundamental approximation which is verified by comparison with the existing exact analysis for the series resonant converter (SRC), the parallel resonant converter (pRe) and the LCC resonant converter (LCC-RC). Comparison of design examples shows a superior performance for the LCC-RC, and less circulating current for the conventional variable-frequency resonant converters than for the phase-shifted control version. Experimental verification is provided for the phase-shifted resonant converters.

The effect of switch capacitance on the zero-voltage switching (ZVS) of resonant converters is studied for the SRC, PRC and LCC-RC. The effect of switch capacitance is more' pronounced for low Q designs. Consequently, it is of primary importance for the LCC-RC whose optimal design requires low Q values. The results have been verified experimentally in an LCC-RC prototype.

A complete analysis and design procedure are provided for the new ZVS-FB-PWM converter, including a new active clamp circuit that completely eliminates the ringing in the I rectifiers. The design procedure and design considerations have been verified with three' experimental prototypes.

The comparison of the resonant converters with the ZVS-FB-PWM converter based on the reactive power required for ZVS, shows that the ZVS-FB-PWM converter is a superior alternative to resonant converters. The ZVS-FB-PWM converter always has less circulating current than the resonant converters when it is designed for a limited ZVS range.

Files
  Filename       Size       Approximate Download Time (Hours:Minutes:Seconds) 
 
 28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access 
[VT] LD5655.V856_1994.S235.pdf 9.52 Mb 00:44:04 00:22:40 00:19:50 00:09:55 00:00:50
[BTD] next to an author's name indicates that all files or directories associated with their ETD are accessible from the Virginia Tech campus network only.

Browse All Available ETDs by ( Author | Department )

dla home
etds imagebase journals news ereserve special collections
virgnia tech home contact dla university libraries

If you have questions or technical problems, please Contact DLA.