A graphical approach for controller design with desired stability margins for a DC–DC boost converter

Abstract

A novel graphical tuning method of PID controller for output voltage regulation of a DC–DC boost converter is proposed. The advantage of the presented method is that the desired robustness level in terms of gain and phase margins can be pre-specified. A technique to limit the noise level in the control signal to a pre-specified value by selecting the derivative gain ( k d ), is also discussed. Simplicity of the technique is an added advantage. Concept of root crossing boundaries along with the gain phase margin tester is applied to compute constant gain and phase margin boundaries in the controller parameters plane. The overlapping area of constant gain and phase margin boundaries within the all stability region is the desired gain and phase margin region (DGPMR). Controller parameters are obtained by computing the centroid of the triangular convex region of the DGPMR. Effectiveness of the proposed tuning strategy is illustrated by simulation and hardware experimental results. Furthermore, the proposed method yields improved closed-loop performance compared to a recently reported tuning strategy in nominal as well as perturbed scenarios.