Modeling and stability analysis of digital current-mode controlled Boost converter in z-domain

The Boost converter with digital current-mode control and leading edge modulation is modeled in z-domain first in this paper. The influences of time delay and zero-order holder (ZOH) on digital controlled converters are taken into consideration. Then, the corresponding circuit model is established and simulations are performed to show the effectiveness of the z-model. It´s shown by simulations based on the circuit model that lower resolution of DPWM module would cause low-frequency oscillation behaviors in digital current-mode controlled DC-DC converters, which is verified by analysis of eigenvalues´ movements based on the z-domain model.