Sliding mode controlled forward converter

The control methods for DC-DC converters should consider wide input voltage ranges and load variations to guarantee stability under wide operating conditions. The switching action of DC-DC converters makes them variable structure systems. Sliding Mode controller is a robust nonlinear controller that can be used for such variable structure systems. The general idea of the SM controller is to create a non-natural stable point by studying the system dynamics and then create conditions to turn on or off the switch. In this work, a forward converter topology that retains the features of a buck converter has been designed and developed. The converter output voltage is maintained constant by using a sliding mode controller under load variations. A systematic design procedure for continuous conduction mode of forward converter has been implemented. The converter and the sliding mode controller was simulated and analyzed under PSIM and MATLAB/SIMULINK environments. Hardware implementation of an analog SMC controller has also been developed for a 30W forward converter model.