Type of Document Dissertation Author Hua, Guichao URN etd-10242005-124114 Title Soft-switching techniques for pulse-width-modulated converters Degree PhD Department Electrical Engineering Advisory Committee
Advisor Name Title Lee, Fred C. Committee Chair Chen, Dan Y. Committee Member Cho, Bo H. Committee Member Jovanovic, Milan M. Committee Member Lin, Tao Committee Member Keywords
- Electric current converters
Date of Defense 1994-04-22 Availability unrestricted AbstractThe concept of soft-switching pulse-width-modulated (PWM) technique was proposed aimed at combining the advantages of both the conventional PWM technique and the resonant technique. This work presents four new families of soft-switching PWM converters: the zero-voltage-switched (ZVS) PWM converters, the zero-current-switched (ZCS) PWM converters, the zerovoltage- transition (ZVT) PWM converters, and the zero-current-transition (ZCT) PWM converters.
The family of ZVS- and ZCS-PWM converters are developed to improve the performance of the ZVS and ZCS quasi-resonant converters, respectively. The principles of operations of these two families of converters are presented, and the merits and limitations are assessed. A number of experimental converters are breadboarded to verify the theoretical analysis.
Both the ZVT-PWM and ZCT-PWM techniques use the concept of shunt resonant network to achieve soft-switching. In this way, the new converters achieve soft-switching without increasing the voltage and current stresses of the power switches and diodes. By using the boost topology as an example, a complete dc analysis of the ZVT-PWM and ZCT-PWM converters is presented, and the dc VOltage-conversion ratio characteristics are derived. Design trade-ofts are examined, and design procedures are established. The theoretical analysis and novel features of the proposed converters are verified on a number of breadboarded converters. Finally, the typical small-signal characteristics of the ZVT -PWM converters are analyzed and verified experimentally by using the boost converter as an example.
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