GPM-based modified internal mode controller for bi-switch DC-DC buck-boost converter

Abstract

This paper addresses the issues of tuning internal mode controller (IMC) for a higher-order bi-switch DC-DC buck-boost converter (BSBBC). The tuning of IMC filter coefficient (λ) is based upon a gain-phase margin (GPM) concept, with an aim to achieve a desired specification of phase margin (PM) and step response specification while considering the robustness and performance criteria. Two well-known statistics of gain margin (GM) and PM are generally used to keep a control system adaptive. A key component of designing an IMC-based controller is choosing the right filter. Based on the filter structure, a robust-modified internal mode control–based proportional–integral–derivative (MIMC-PID), MIMC-PID with lag compensator (MIMC-PID-LAG), MIMC-based proportional–integral–double-derivative (MIMC-PID²) and MIMC-PID with lag-lead compensator (MIMC-PID-LAG-LEAD) are designed for voltage mode control of a BSBBC. The attractiveness of this paper lies in the fact that the formulation of controller can be easily achieved by following a basic conventional IMC approach. Hence, eliminating the need for highly complicated mathematical methods. The proposed technique exhibits sharp reference tracking and good disturbance rejection with a minimal integral error performance, when compared quantitatively with other evolved controllers. In this paper, robustness is analysed in frequency and time-domain parameters through simulation results, and examinations of hardware results are carried out on an 80 W laboratory prototype converter.