Comparative analysis of performance of the SEPIC converter using LQR and PID controllers

The purpose of this study is to design a LQR controller for the SEPIC (Single-Ended Primary-Inductor Converter) converter which is widely employed in industrial DC-DC power conversion and is also starting to see widespread use in PV applications. Circuit-Averaging-Method is used to acquire the mathematical model of the given system. Controllers are designed based on the Small-Signal model. LQR and PID controllers are used to control SEPIC and their performances are analyzed. A Kalman Filter is used as an observer to acquire the system states which are necessary in LQR control. The performances of the system with given controllers are analyzed with simulations in MATLAB/SIMULINK. It is seen that the LQR approach outperforms PID in terms of various criteria.