PROJECT TITLE :

Decoding and Synthesizing Transformerless PWM Converters

ABSTRACT:

Pulse-width-modulated (PWM) converters have been widely applied for power processing, and they are sometimes the stems of alternative varieties of converters, like quasi-resonant, Z-source, and switched-inductor hybrid converters. Development of PWM converters has been spanning over a century, starting from the buck converter. The well-known PWM converters embody buck, boost, buck-boost, Ćuk, single ended primary inductive converter (SEPIC), zeta, Z-source, quasi-Z source, etc. Many attempts have been proposed to develop these converters based mostly mostly on canonical cell ideas and by introducing further LC filters to the cells. This paper presents an enhancement to the layer and graft schemes by introducing the concepts of dc voltage/current offsetting, capacitor/inductor part splitting, diode grafting, and inverse operation of PWM converters. The PWM converters, that can be operated in continuous conduction mode (CCM) or discontinuous conduction mode (DCM), therefore can be synthesized systematically according to decoded transfer gains. Decoding and synthesizing PWM converters uniquely bridge transfer gains to converter topologies and give readers a comprehensive understanding of PWM-converter evolution from the first converter, the buck converter. Additionally, in this paper, the Ćuk, SEPIC, and zeta converters all with the identical transfer gain of D/(one - D) are proved to be corresponding to the buck-boost converter with an further LC filter. For further illustrating the proposed approaches, numerous sorts of Z-source converters, switched-capacitor/switched-inductor hybrid converters, and one-stage interleaved converter are reviewed, and new PWM converters are developed.