Digital Implementation of Sliding Mode Controllers with DC-DC Buck Converter System

In this paper, a benchmark system of a dc-dc buck converter is studied using conventional continuous time sliding mode control and advanced discrete time designs, with an objective to show that the latter design gives a better performance of the system since both control design and simulation are done in discrete time. This is verified both in simulation as well as in a practical experimental setup with dc-dc buck converter. The classical sliding mode control is designed with the continuous time model and for the discrete time model, relative degree one (RD13) sliding surface and the more recent relative degree two (RD2) sliding surface designs are compared. It is shown that the performance of the system is best for the last case, thus establishing the idea that advanced discrete time sliding mode control designs lead to performance improvement in a practical system.