Closed-loop control of buck-boost converter using the PID controller

Abstract

In the modern world, the most demanding control systems are based on PID controllers because of their reputed performance in nonlinear control systems. Tuning the PID controller is a major part of the feedback PID controller design. This research is focusing on the design of PID controller for the DC-DC Buck-Boost converter to improve output voltage regulation. It is a challenging task to tune the PID controller to achieve stable output in the DC-DC Buck-Boost converter because of nonlinearities. Firstly, to design a PID controller for the DC-DC Buck-Boost converter, a model of an open-loop DC-DC Buck-Boost converter using state-space averaging is developed. State-space averaging is used in the modified Ziegler-Nichols method. From this model, the stability of the system is analysed based on an open-loop system margin and zero and pole placements. Moreover, the system response in steady-state, under the line variation and load variation are also analysed. Variations occurred in the output voltage are due to variations in the load resistor or source voltage. A MATLAB simulation is conducted to analyse the initial results. It can be shown that the PID controller without overshoot gave the best performance among the P, PI and PID controllers.