A novel stability analysis method based on Floquet theory for cascaded DC-DC converters system

The stability of the cascaded power converters system is an important design consideration, since the interaction among the individual converters in the cascaded system can lead to the degradation of the system stability and dynamical performances, even make the system unstable. In this paper, the stability analysis methods for the cascaded power conversion system are reviewed at the beginning. Following, the Floquet theory is firstly employed into the stability analysis for cascaded DC-DC converters. A two-stage cascaded DC-DC converter system is taken as an example in this paper and its stability criterion based on Floquent theory is derived. Finally, PSIM simulation results prove that the proposed stability criterion with Floquet theory is more accurate than Middlebrook impendence criterion. Moreover, the proposed stability analysis method can be further used in multi-stage cascaded converters, which provides a good stability analysis way for cascaded DC-DC converters.