Design and Robustness Analysis of a PID Based Sliding Mode Controller for a dc-dc Converter

This study deals with the design and analysis of a dc-dc converter operating in continuous conduction mode with Proportional-Integral-Derivative control and PID based Sliding Mode Control (SMC). A small signal model is developed using Switching Flow Graph (SFG) from which the control coefficients for the PID controller is selected. PID based SMC uses a control law which constrains the weighted sum of the voltage error, its derivatives and the integral of the voltage error to zero. The equivalent control technique is used in its design which makes the converter more suitable for fixed frequency operation. Sensitivity of these controllers to supply voltage disturbances and load disturbances is studied and results are presented.