Generalized Average Modeling 기법을 이용한 단상 하이브리드 변압기의 AC/DC 컨버터 소신호 모델

Abstract

This paper proposes a small-signal modeling approach for a AC/DC converter in single-phase hybrid transformer with an AC input. In contrast to a topology like a boost PFC which uses a rectification stage, the AC/DC converter cannot be accurately modeled using classical small-signal techniques. In addition, single-phase topologies require alternative modeling methods because of the zero average current of the input inductor and input voltage, which is different from a three-phase case using a dq transformation. In this paper, a Generalized Average Modeling (GAM) technique is employed to obtain an accuate small-signal model for the totem-pole PFC circuit. This technique allows for the separation of real and imaginary components of voltage and current, even when the average input values are zero, enabling an effective small-signal modeling. The accurate model facilitates a more precise analysis of the dynamic characteristics of the AC/DC converter circuit than conventional approaches. Furthermore, it lays a groundwork for designing suitable current and voltage controllers. The accuracy of the proposed modeling technique is validated by circuit simulations and experiments with a 300 W prototype converter.