DESIGN OF SLIDING MODE CONTROLLER FOR ISOLATED FULL BRIDGE DC-DC CONVERTER

Abstract

Non-linear control theory was developed due to inherent short-comings of' the linear control theory. It also has the advantages like robustness against uncertainties and parameter variations. So it is widely accepted around the world as a better technique for the control of non-linear systems. Most of the real systems being non-linear in nature bind this control technique most attractive. Classical control techniques require accuracy in design of the system before they are implemented. Classical control techniques like are effective in stabilizing the system, but with the introduction of parameter uncertainties this becomes difficult. Particularly some systems exhibit limit cycle; i.e. continuous oscillations about the equilibrium point. Sliding mode control technique is a non-linear control technique characterized by simplicity in analysis, design, high efficiency and robustness to parameter uncertainties. In this thesis introduction to sliding mode control design for Isolated DC-DC converter has been presented and the phenomenon of chattering has been discussed. Boundary layer solution method of chattering control has been illustrated. Practical application of Sliding mode control has been illustrated by applying it to Isolated Full-Bridge DC-DC converter. The Isolated Full-Bridge DC-DC converter prototype model has been developed using MATLAB/SIMULINK and dSPACE control desk. Simulation and hardware results verify the robustness and simplicity of sliding mode control technique. So Sliding mode control technique assures a satisfactory technique in practice.