Effect of implementing sliding mode control on the dynamic behavior and robustness of switch mode power supply (buck converter)

The focus of this paper is on the implementation of sliding mode control (SMC) for switch mode power supply. A brief analysis of the control structure is explained followed by a block diagram showing the internal structure of the control loops and the way they are connected to the converter. The buck converter was chosen as an example and the simulation model of the converter with its control circuit was build-up in matlab/simulink/sup /spl trade//. Once the circuit was build-up, the study of the dynamic response of buck converter controlled by SMC is done. The output voltage, inductor current, and the instant switching frequency are analyzed and studied in the following three regions: turn on region, line and load variation region, and finally components variation region. In the third part concerning robustness a wide range of change of the buck converter component parameters values are applied individually, and the study of the effect of SMC on the converter response due to these variations are analyzed.