Design of robust PID controller for Buck converter using Bat algorithm

Abstract

Buck converters are still used as an efficient step down DC-DC converters for constant load voltage for many power supply applications under variable input voltage and different loading conditions. In most of the applications DC-DC converters are controlled by either voltage or by current mode controller. DC-DC converters exhibit non-linear behavior due to switching, hence controller design comes with complexities. With ordinary PI controller, dynamic response of Buck converter is sluggish and exhibits large deviations. In this paper robust PID controller based on H∞ paradigm has been designed for voltage mode controlled buck converter with both variable input voltage and load variation. The controller design problem has been formulated as mixed sensitivity minimization problem and solved using bat algorithm. From the results obtained, the designed controller exhibits robust behavior by satisfying the robust stability criterion. The design and simulation has been carried out using MATLAB/SIMULINK and results verify the robustness of the controller for large input voltage and load variations.