Current mode control with auxiliary controller of DC-DC switching buck converters with robust performance

The purpose of this paper is to present an improvement in the conventional CIC (Current Inyected Control) [3] current mode control of switching DC-DC converters, consisting of the addition of an auxiliary controller in the control loop. This model-based controller preserves the closed loop small-signal bandwidth (including loop gain crossover frequency and stability margins) of Buck derived converters over a large range of variation of the power stage passive elements, the load and the line voltage. Moreover, this control scheme shows much better disturbance rejection (closed loop impedance and audiosusceptibility) than conventional CIC. An experimental Buck prototype has been tested. Its dynamic response and disturbance rejection with conventional and reference-model based Robust-CIC control are compared in this paper, showing a superior large signal response of the proposed scheme.