Abstract
A systematic and unified approach to modeling PWM dc/dc converters based on the graft scheme is presented in this paper. With the graft scheme, the typical PWM switch-mode converters, such as buck-boost, Cuk, Zeta and Sepic, can be generated from the two basic converters, buck and boost. The small signal models of these converters can be, therefore, derived by combining those of the buck and boost. Using the proposed approach can help to yield highly related dynamic models of the converters in a family, and, in addition, physical insights between the converters can be readily identified. This has made the proposed modeling method be valuable and viable.