Large-signal stability of a boost regulator by means of linear control laws

The problem of stabilizing a boost regulator in large-signal situations using linear control laws is investigated in this paper. The control law is derived by means of a circuit-oriented procedure. After establishing a large-signal circuit model for the boost regulator including state-feedback, conditions for passivity in the resulting two-port are studied. As a consequence, a control law is directly derived from two-port passivity conditions, this ensuring regulator global stability even if the control saturation is taken into account. Subsequently, a linear analysis is performed in order to design the desired dynamics and robust behavior of the switching regulator. The linear analysis shows that only one feedback gain is necessary, provided that the coordinates of the equilibrium point are known. The use of regulator root locus, gain margin and phase margin diagrams as a function of the feedback gain allows to choose the proper value of this gain solving a certain trade-off for good dynamic response and robust behavior. ACSL simulations verify the analytical predictions.