Theoretical Analysis of Bidirectional Bifurcation Phenomena in DC Cascaded Converter Systems

Abstract

DC-DC converters are major components of a DC cascaded converter system. The converters interface with external power inputs, internal DC buses and loadings of subsystems. Stability of these constituent converters under all operating conditions is vital to the operation of the whole system. Current research results show that the system's stability can be guaran-teed when the system's parameters are within specific ranges, which are similar to the results obtained from standalone DC-DC converters. However, DC cascaded systems are high order systems and the dynamic behaviors are more complex than their standalone counterparts. In this paper, we identify and analyze the bidirectional bifurcation phenomena in the current-mode controlled DC cascaded system. Based on the derived averaged model, the bidirectional bifurcation phenomena and the associated mechanism will be studied in depth. Finally, the validity of the analysis is verified by laboratory experiments.