Negative impedance stabilizing controls for PWM DC-DC converters using feedback linearization techniques

Power electronic converters, when tightly regulated, have constant power sink characteristics at their inputs. This is a destabilizing effect, which is known as negative impedance instability, for the DC/DC converters feeding these loads in a multi-converter power electronic system. In this paper, necessary and sufficient conditions of stability for PWM DC/DC converters with constant power and conventional constant voltage loads are expressed. A nonlinear robust stabilizing controller based on feedback linearization techniques is proposed. Furthermore, the stability of the proposed controller for the Buck converter using the second theorem of Lyapunov is verified.