Stability and Periodicity of Discrete SM Controlled Buck Converter with Parasitic Parameters

This paper investigates the problems of stability and periodicity for the discrete sliding mode (SM) controlled DC-DC buck converters subject to parasitic parameters. The loss resistance of power switch, conduction voltage and conduction resistance of diode, equivalent series resistance of inductor are first considered and modeled for buck converters. After the discretization of SM controlled buck converter system, the stability condition is deduced, proving that there exist a attractive region in phase plane which affected by the sampling time. The sufficient and necessary condition of periodicity is given and the influence of parasitic parameters on dynamic trajectory is analyzed and further it is proved not affect the system periodicity under some restricted conditions. Simulations validate the proposed research.