A control strategy to stabilize PWM dc-dc converters with input filters using state-feedback and pole-placement

Abstract

LC filters at the input of dc-dc converters can lead to instabilities due to filter interactions with the converter control. Conventional methods to remedy this issue usually employ external resistors to damp filter oscillations. However such dissipative damping of input filter degrades the converter efficiency. In this paper we propose an alternate solution to this problem using a full state-feedback controller combined with a PI-control. This control algorithm assures stability of the system without using any passive components in the filter circuit and thus avoiding any undesirable losses. Moreover it guarantees adequate level of performance using a varying gain state-feedback and pole-placement. Simulation studies are carried out to confirm the effectiveness of the suggested control strategy under large perturbations.