Nonlinear P-I controller design for switchmode DC-to-DC power converters

Extended linearization techniques are proposed for the design of nonlinear proportional-integral (P-I) controllers stabilizing, to a constant value, the average output voltage of pulsewidth modulation (PWM) switch-regulated DC-to-DC converters. The Ziegler-Nichols method is used for the P-I controller specification, as applied to a family of parametrized transfer function models of the linearized average converter behavior around a constant operating equilibrium point of the average PWM controlled circuit. The form in which the designed nonlinear P-I controllers are to be used in the actual discontinuous PWM feedback scheme is also indicated. The boost and the buck-boost converters are specifically treated, and the regulated performance is illustrated through computer simulation experiments