[IEEE APEC '99. Fourteenth Annual Applied Power Electronics Conference and Exposition. 1999 Conference Proceedings (Cat. No.99CH36285) - Dallas, TX, USA (1999.03.18-1999.03.18)] APEC '99. Fourteenth Annual Applied Power Electronics Conference and Exposition. 1999 Conference Proceedings (Cat. No.99CH36285) - Analysis of a class of ZVT DC/DC converters based on pulse amplitude modulation controlled by duty cycle