A novel constant frequency sliding mode control of DC-DC converters

Sliding Mode Control (SMC) is a robust and easy to design control law, which can be applied to linear and nonlinear systems. It has been of great research interest for applications in power electronics and motor drives. Conventional/First order sliding mode suffers from chattering of the control input, which when used for DC-DC Converters, results in variable switching frequency of the power switch. This will lead to more switching losses and also makes the design of the converter passives difficult. This research work presents a modified version of SMC, called Constant Frequency SMC (CFSMC), which ensures that DC-DC Converters operate at constant switching frequency and yet remain as robust and easy to implement as the conventional SMC. The theory is developed and verified through simulations for Boost, Buck-Boost, SEPIC and Cuk Converters in MATLAB/SIMULINK.