Active stabilization of DC-DC converters with input LC filters via current-mode control and input voltage feedback

Abstract

LC filters at the input of a DC-DC converter can introduce instability when used with feedback control. Traditional methods of addressing this issue focus on sizing the input filter to avoid instability, introducing passive damping elements, and, most recently, using state feedback to actively stabilize the input filter. This work presents a new method of actively stabilizing the input filter via current-mode control, using a control law that incorporates an additional feedback term for the input capacitor voltage. The stability of a buck converter under such a control law is investigated via root locus, and analysis is verified by experimental results.